









V '^'' %f :*« ■ V* •' W- V -■**"■- **^^*'' •'" 









» >..^^ «'»^V '^..^^ .^iffl^'o ^-..^* .* 











>/-'r.^*%o^^ V*^^\<^ %-'f:T.%G^^ V*^^*<^ %-'f:r.\o^" ' 






















y .-■■■■^ 



1 of Forestry, U. S. Dept. of Agriculture. 




>' 



•:^' 



U. S. DEPARTMENT OF AGRICULTURE. 

BUREAU OF FORESTRY— BULLETIN No. 41 

GIFFORD PINCHOT, Forester. 



SEASONING OF TIMBER. 



HERMANN VON SCHRENK, 

In Charge of Mississippi Valley Laboratory, Bureau of Plant Industry, 



ASSISTED BY 



REYNOLDS HILL, 

Agent, Bureaii of Forestry. 




WASHINGTON: 

GOVERNMENT PRINTING OFFICE. 

10 3. 



Tj- 



UonofiW* 



e) 



^ 

-b ^ 
'b 



LETTER OF TRANSMITTAL 



U. S. Department of Agriculture, 

Bureau of Forestry, 
Washington^ D. O. , Feiruary 6', 1903. 
Sir: I have the honor to transmit herewith a report entitled "Sea- 
soning of Timber," by Dr. Hermann von Schrenk, pathologist in 
charge of the Mississippi Valley Laboratory, Bureau of Plant Industry, 
assisted by Reynolds Hill, agent, Bureau of Forestry, and to recom- 
mend its publication as Bulletin No. 41, Bureau of ForestrJ^ The illus- 
trations (of which there are eighteen full-page plates and sixteen text 
figures) are believed to be necessary to a full understanding of the 
text by the reader. 

Respectfully, Gifford Pinchot, 

Forester. 
Hon. James Wilson, Secretary. 



NUV 27 IM)6 

D.ofa 



5^ 



CONTENTS 



I. Introduction 5 

II. Distribution of water in timber 7 

Local distribution of water in wood and tree 7 

Seasonal distril)ution 7 

III. Relation of water to the decay of timber 8 

IV. What seasoning is 9 

Difference between seasoned and unseasoned timber 9 

Manner of evaporation of water 10 

V. Seasoning and preservative treatment 12 

Seasoning and the leaching of salts 12 

Seasoning and the processes of preservation 17 

VI. Advantages of seasoning 19 

Saving in freight 19 

Use of cheap timbers 19 

Prevention of checking and splitting 22 

VII. How timber is seasoned 24 

Kiln drying 24 

Seasoning in other countries 24 

Seasoning by steaming 26 

Seasoning by immersion in water 27 

Seasoning by boiling in oil 2S 

Out-of-door seasoning , 28 

VIII. Plan for seasoning tests. 29 

IX. Seasoning tests with Lodgepole Pine .30' 

Tests at Bozeman, Mont .31 

Making and delivery of ties 31 

Piling of ties 32 

Wind direction 33 

Intervals of cuttings .3.3 

Preliminary results of seasoning tests 34 

Seasoning after treatment with zinc chlorid 36 

Individual variation in seasoning' 37 

Variation by months 39 

Cost of piling 40 

X. Seasoning of oak timber 42 

XI. Tests with telephone poles 43 

Decay of poles 44 

Plans for preventing decay of poles 44 

XII. Plans for future work ^ 45 

Seasoning of oak timbers 45 

Seasoning of pine in the Southern States 45 

Seasoning of gum timber ,.'. .'.."j. ■.'•.' 46 

Pacific Coast tests ..^ .' 46 

XIII. Conclusions and recommendations 46 

Appendix 47 

3 



.LUSTRATIONS. 



PLATES. 

Page. 
Plate I. Loading seasoned ties of Lodgepole Pine at Shieridan, Wyo . . Frontispiece. 
II. Wood-deatroying fungus {Lentinus lepideiis) on Red Fir tie, South 

DaliOta _ 8 

III. Fig. 1. — Wliite Oali; ties seasoned too fast. Fig. 2. — Pile of poorly 

seasoned car lumber 8 

IV. Piling Baltic Pine on the Great Western Railway, England 12 

V. Fig. 1.— Tie yard, Sheridan, AVyo., April, 1902; solid piles. Fig. 2.— 

Tie yard, Sheridan, Wyo., September, 1902; open piles 12 

VT. Making a tie out of Lodgepole Pine timber, Bozemau, Mont 16 

VII. Fig. 1. — Lodgepole Pine forest after tie timber has been cut out. 

Fig. 2. — Cutting of ties in the woods 16 

VIII. Fig. 1. — Dragging ties to the flume. Fig. 2. — Tie piles at the flume.. 20 
IX. Fig. 1. — Throwing ties into flume. Fig. 2. — Ties ready for the 

flume 20 

X. Fig. 1. — Tie flume. Fig. 2. — Another view of flume 20 

XI. Fig. 1. — End of flume at railroad track. Fig. 2. — Another view of 

same 20 

XII. Fig. 1. — Landing platform, Bozeman, Mont. Fig. 2. — Another view 

of landing platform 24 

XIII. Fig. 1. — Lodgepole Pine, solid pile. Fig. 2. — Lodgepole Pine, half- 

open pile 24 

XIV. Lodgepole Pine, open-crib pile. Fig. 1. — Before treatment. Fig. 2. — 

After treatment 32 

XV. Fig. 1. — Triangular tie joiles. Fig. 2. — Lodgepole Pine piled to test 

influence of prevailing winds on dr}'ing 32 

XVI. Oak piles, showing lowest tier on the ground — a poor method 32 

XVII. Oak piles, showing methods of building a roof 40 

XVIII. Open-crib oak piles, southern Illinois , 40 

TEXT i'TGURES. 

Fig. 1. Diagram showing absorption and loss of water by dry wood 11 

2-6. Manner in which soluble salts leach out from treated timber 12-14 

7. Diagram showing length of life of Oak and Beech ties, French Eastern 

Railway , 21 

8. S-irons used to prevent checking 23 

9. Method of applying S-irons to prevent splitting 23 

10. Pile of ties on French Eastern Railway 24 

11. Diagram showing average loss in weight by seasoning of Oak and 

Beech timber during one year, French Eastern Railway 26 

12. Diagram showing rate of drying of green ties 35 

13. Diagram showing rate of seasoning of Lodgepole Pine ties treated 

with zinc chlorid 36 

14. Diagram showing loss of weight of 3 ties, a mean and two extremes. . 37 

15. Diagram showing percentage loss of water of Lodgepole Pine timber 

during various months, Bozeman, JMont., 1902 40 

16. Diagram showing specific gravity of Lodgepole Pine timber cut 

during successive months 41 

4 



SEASONING OF TIMBER. 



I. INTRODUCTION. 

In a recent report on the general subject of timber pi-eservation " it 
was pointed out that there were a number of problems in connection 
with this subject requiring further investigation. These problems 
related to various stages in the preservation of timber, the prepara- 
tion of timber for treatment, methods of treatment, and the final 
disposition of treated timber. The present bulletin is the first of a 
series which it is intended to issue from time to time, and deals with the 
preliminar}' seasoning which precedes the actual chemical treatment. 

In the report referred to, it was pointed out that one of the problems 
requiring further investigation was the length of life of anj' given tim- 
ber as affected by seasoning. Although it has been known for a long 
time — and the fact is daily in practical evidence — that there is a marked 
difference in the length of life of seasoned and of unseasoned timber, 
the consumers of lumber have shown verj^ little interest in the season- 
ing of timber except for the purpose of doing away with the evils 
which result from checking, warping, and shrinking. For this pur- 
pose both kiln diying and air seasoning are largely in use. Kiln dry- 
ing, which dries the wood at a uniforml}' rapid rate by heating it in 
inclosed rooms, has become a part of the car-building industry and of 
the manufacture of furniture, vehicles, tools, and many other articles 
in ordinaiy use. Without it the construction of the finished product 
would often be impossible. Nevertheless, much unseasoned or imper- 
fectl}^ seasoned lumber is used in car construction, as is evidenced by 
subsequent shrinkage and warping. 

Complaints are dailj^ made b}^ railroad managers that their freight 
cars twist and warp out of shape more than they did years ago. The 
explanation for this is probabl}- to be found in the tremendous devel- 
opment in recent j'ears of the industries which require lumber for 
building purposes. The manufacturer of structui'al lumber is so hard 
pressed for lumber that he is forced to send out a poor product, which 
the consumer is willing to take in that condition rather than to wait 
several weeks or months for thoroughly seasoned material. As a 
result, properly seasoned wood commands a high price, and in some 
cases can not be obtained at all. Wood seasoned out of doors, which 
by many is supposed to be much superior to kiln-dried timber, is 

«The Deca}' of Timber, and Methods of Preventing It. By Hermann von Schrenk. 
(Bull. 14, Bureau of Plant Industry, U. S. Dept. of Agriculture, 1902.) 



6 ■ SEASONING OF TIMBEE. 

becoming very scarce indeed, as the demand for any kind of wood is 
so g-reat that it is thought not to pay to hold timber for the time neces- 
ssivj to season it proper!}-. 

How long this state of affairs is going to last it is difficult to say, 
but it is believed that a reaction will come when the consumer learns 
that in the long run it does not paj' to use poorly prepared material. 
Such a condition has now arisen in connection with another phase of 
the seasoning of timber. As alreadj' said, it is a commonly accepted 
fact that dry timber will not decay nearlj- so fast as. wet timber. 
Nevertheless, the immense superioritj^ of seasoned over unseasoned 
wood for all purposes where resistance to decay is necessary has not 
been sufficiently recognized. In the times when wood of all kinds was 
both plentiful and cheap it mattered little in most cases how long it 
lasted. Wood used for furniture, flooring, car construction, etc., 
usually got some chance to dry out after it was placed in use. The 
wood which was exposed to decaying influences was generally selected 
from those woods which, whatever their other qualities might be, 
would resist deca}' longest. At first ties were made wholly of White 
Oak, and, judging from recently compiled data, this wood alone was 
used for many years. It lasted longer than other timber, and was hard 
as well. The service which it gave was an ample return on the invested 
cost, and no one thought at that time that it was at all necessarj^ to 
devise means for lengthening that ser^aee. Ties were cut in an}' way 
and at an}^ time, and were laid sometimes two days after cutting, some- 
times not for six months or a year, during which time they may have 
Iain in the woods, in a ditch full of water, or piled haphazai'd. 

To-day conditions have changed, so that the 'White Oak can no longer 
be used economically to the same extent as in former j-ears. Inferior 
timber with less lasting qualities has been pressed into service, not 
onlj' for ties, but for fence posts, bridge material, piles, etc. Although 
haphazard methods of cutting and subsequent use are still much in 
vogue, there are many signs that both lumbermen and consumers 
are awakening to the fact that such carelessness and wasteful methods 
of handling structural timber will no longer do, and must give way 
to more exact and economical methods. The reason why many timber 
merchants and consumers are still using the older methods is perhaps 
because of long custom, and because they have not vet learned that, 
though the saving to be obtained by the application of good methods 
has at all times been appreciable, now, when timber is more valuable, 
a much greater saving is possible. The increased cost is really very 
slight, and is many times exceeded by the value of the increased service 
which can be secured. 

In the following pages a discussion of the principles applying to the 
seasoning of wood is presented, together with some preliminarj' results 
of tests made during the past 3'ear. It is thought advisable to publish 
these results at this time, because the preliminary figures obtained are 
so suggestive that thej^ may prove of value even in their present 
incomplete form. It is to be understood, however, that the experi- 



DISTRIBUTION OF WATEE IK TIMBER. ' 7 

ments described are merely the first of a large series, some of which 
are now under way, and which it is hoped will be carried on continu- 
ouslj' for as manj' years as may be necessary to obtain sufficient data 
to make the conclusions reached pei-fectlj^ accurate. 

II. DISTBIBUTIOIT OF WATER IN TIMBER. 

As seasoning means essentially the more or less rapid evaporation 
of water from wood, itVill be necessary to discuss at the ver}' outset 
where water is found in wood, and its local and seasonal distribution 
in a tree. 

LOCAL DISTRIBUTION OF WATER IN WOOD AND TREE. 

A concise description of the distribution of water in wood was pre- 
sented in an earlier bulletin of this Bureau, and as it covers the matter 
fully, it is quoted in full here: " 

Water may occur in wood in three conditions: (1) It forms the greater part (over 
90 per cent) of the protoplasmic contents of the living cells; (2) it saturates the 
walls of all cells; and (3) it entirely or at least partly fills the cavities of the lifeless 
cells, fibers, and vessels; in the sapwood of jjine it occurs in all three forms; in 
the heartwood only in the second form, it merely saturates the walls. Of 100 pounds 
of water associated with 100 pounds of dry-wood substance taken from 200 pounds 
of fresh sap^'ood of White Pine, about 35 pounds are needed to saturate the cell walls, 
less than 5 pounds are contained in living cells, and the remaining 60 pounds partly 
fill the cavities of the wood fibers. This latter forms the sap as ordinarily under- 
stood. It is water brought from the soil, containing small quantities of mineral 
salts, and in certain species (Maple, Birch, etc.), it also contains at certain times 
a small percentage of sugar and other organic matter. These organic substances are 
the dissolved reserve food, stored during winter in the pith rays, etc., of the wood 
and bark; generally but a mere trace of them is to be found. From this it appears 
that the solids contained in the sap, such as albumen, gum, sugar, etc., can not 
exercise the influence on the strength of the wood which is so commonly claimed for 
them. 

The wood next to the bark contains the most water. In tlie species which do not 
form heartwood the decrease toward the pith is gradual, but where this is formed 
the change from a more moist to a drier condition is usually quite abrupt at the sap- 
wood limit. In Longleaf Pine, the wood of the outer 1 inch of a disk may contain 
50 per cent of water, that of the next, or second inch, only 35 per cent, and that of 
the heartwood onlj' 20 per cent. In such a tree the amount of water in any one sec- 
tion varies with the amount of sapwood, and is therefore greater for the upper than 
the lower cuts, greater for the limbs than stems, and greatest of all in the roots. 

Different trees, even of the same kind and from the same place, differ as to the 
amount of water they contain. A thrift}' tree contains more water than a stunted 
one, and a young tree more than an old one, while the wood of all trees varies in 
its moisture relations with the season of the year. 

SEASONAL DISTRIBUTION. 

It is generally supposed that trees contain less water in winter than 
in summer. This is evidenced bj' the popular saying that "the sap is 
down in the winter." This is probably not always the case. Some trees 

aXimber. By Filibert Eoth. (Bull. 10, Division of Forestry, U. S. Dept. of Agri- 
culture, 1895.) 



8 SEASONING OF TIMBER. 

contain as much water in winter as in summer, if not more. The aver- 
rage weight of Lodgepole Pine ties of the same size cut at Bozeman, 
Mont., in June, 1902, was 1.57 pounds; in July, 144 pounds; in August, 
160 pounds; in September, 157 pounds; in October, 164 pounds. It is 
probable that this increase would keep up throughout the winter. 

Of the varying amounts of water in the trees of one region during 
the same period of different 3rears, little or nothing is known. It is 
hoped that the tests now in progress will give some indications in that 
direction. 

III. RELATION OE WATER TO THE DECAY OF TIMBER. 

The intimate relation existing between the presence of water in wood 
and the rate at which wood decays requires a brief reference to the 
causes of wood decay. A full account of the factors which bring, 
about deca}^ has recentl}^ been published," and those interested are 
refei'red to that publication for details. It will be sufficient at this 
point to say that low forms of plant life called fungi grow in wood, 
and by so doing disintegrate and dissolve portions of the wood fiber. 
As a result of this, the wood changes in its physical properties and is 
called decayed. When the fungus has extracted a sufficient amount 
of material, it forms, on the outside of the wood, fruiting bodies 
known as punks or toadstools, containing spores, which are blown 
about and infect sound wood. PL II shows a Eed Fir railroad tie in 
position, with the fi'uiting body of one of the most common of these 
wood-destroying fungi {Lentinus lejyidexhs) gi-owing out from one side. 
The ballast has been partly scraped away to show the whole fungus. 
Fig. 2 shows the fungus on a larger scale. White, filmy fungus 
threads grow through the mass of sandy ballast and spread to adjacent 
ties. 

The conditions necessary for the growth and development of wood- 
destroying fungi are (1) water, (2) air, (3) organic food materials, and 
(4) a certain amount of heat. The wood fiber and the organic substances 
found in the living cells of sapwood, such as albuminous substances, 
starch, sugar, and oils, form the food supply necessary to start the 
growth of the fungus threads. A further requirement is oxygen; no 
growth will take place under water or in the ground at depths of 2 
feet or more, the depth varying with the character of the soil. The 
best examples of this necessity for oxygen can be found in the way in 
which fence posts and telegraph or telephone poles decay at points 
just at or just below the surface of the ground, where there is a 
balance between the supplj^ of air and of water. 

For practical purposes water is the most important factor. With- 
out water no fungus growth, and consequently no decay, is possible. 
"Dry rot," a form of decay in which the wood turns to a drj"-, brittle. 



a The Decay of Timber, and Methods of Preventing It. By Hermann von Schrenk. 
(Bull. 14, Bureau of Plant Industry, U. S. Dept. of Agriculture, 1902.) 



+ 1, Bureau of Forestiy, U. S- Dept. of Agriculture. 




FiQ. 1.— Fruiting Body of Fungus on Tie in Position, 




Fig. 2.— a Near View of Fig. 1. 

WOOD-DESTROYING FUNGUS iLENTINUS LEPIDUSi ON RED-FIR TIE, SOUTH 

DAKOTA. 



3ul. 41, Bureau of Forestry, U. S. Dept. of Agriculti 





WHAT SEASONING IS. 9 

charcoal-like substance, is commonh' supposed to take place without 
any water. Such is not the case, however. The atmospheric mois- 
ture is sufficient to permit growth of the dry-rot fungus even if no 
moisture is contained in the wood. Too much water will prevent 
fungus growth, because it shuts off the air supply. The amount of 
water necessarj^ to ]iermit the growth of fungi is very small. Wood 
freshly cut contains more than enough at all seasons of the year to 
support fungus growth. 

From the foregoing it will be clear that the removal of water from 
timber brings about a condition which during its continuance does not 
allow of the growth of wood-destroying fungi. In other words, din/ 
wood will not rot or decaj^. 

IV. WHAT SEASONING IS. 

DIFFERENCE BETWEEN SEASONED AND UNSEASONED TIJVIBER. 

Seasoning is ordinarily understood to mean drjdng. When exposed 
to the sun and air the water in green wood rapidlj^ evaporates. The 
rate of evaporation will depend on the kind of wood, the shape of the 
timber, and the conditions under which the wood is placed. Pieces 
of wood completely surrounded by air, exposed to the wind and the 
sun, and protected b}^ a roof from rain and snow, will dry out very 
rapidlj^; while wood packed close together, so as to exclude the air, or 
left in the shade and exposed to rain and snow, will probably dry out 
very slowly. 

But seasoning implies other changes besides the evaporation of watfer. 
Although we have as yet only a vague conception as to the exact nature 
of the difference between seasoned and unseasoned wood, it is very 
probable that one of these consists in changes in the albuminous sub- 
stances in the wood fiber, and possibly also in the tannins, resins, and 
other incrusting substances. Whether the change in these substances 
is merely a drying out, or whether it consists in a partial decomijosi- 
tion, is as yet undetermined. That the change during the seasoning- 
process is a profound one there can be no doubt, because experience 
has shown again and again that seasoned wood fiber is very much 
moi'e permeable, both for liquids and g'ases, than the living, unsea- 
soned fiber. One can picture the albuminous substance as forming a 
coating which dries out and possibl}' disintegrates when the wood 
di-ies. The drying out may i-esult in considerable shrinkage, which 
may make the wood fiber more porous. It is also jDossible that there 
are oxydizing influences at work within these substances, which result 
in their disintegration. 

Whatever the exact nature of the changes may be, one can say 
without hesitation that exposure to the_wind and air brings about 
changes in the wood which are of such a nature that the wood becomes 
drier and more permeable. When seasoned by exposure to live 



10 



SEASONING OF TIMBER. 



steam, similar changes maj- take place. The water leaves the wood in 
the form of steam, while the organic compounds in the walls probably 
coagulate or disintegrate under the high temperature. 

MANNER OF EVAPORATION OF WATER. 

• The evaporation of water from timber takes place largely through 
the ends, i. e., in the direction of the longitudinal axis of the wood 
fibers. The evaporation from the other surfaces takes place very 
slowly out of doors; with greater rapidity in a kiln. The rate of 
evaporation differs both with the kind of tim ber and its shape. Thin 
boards and beams dry faster than thicker ones; sapwood dries faster 
than heartwood. and j)ine more rapidly than oak. Tests made during 
the past summer showed little difference in the rate of .evaporation in 
sawed and hewn ties, the results, however, not being conclusive. 
Air-diying out of doors takes from two months to a year, the time 
depending on the kind of timber and the climate. No data have been 
obtained as to the rate of evaporation out of doors. This is one of 
the questions now under investigation. 

After wood has reached an air-dry condition it absorbs water in 
small quantities after a rain, or during damj) weather, much of which 
is immediately lost again when a few warm, dry days follow. In this 
way wood exposed to the weather will continue to absorb water and 
lose it for indefinite periods. When soaked in water, seasoned timber 
absorbs water rapidty." This at first enters into the wood through 
the cell walls. When these are soaked the water will fill the cell 
lumen, so that if constantly submerged the wood may become com- 
pletely filled with water. The following figures show the gain in 
weight by absorption of several coniferous woods, air-dry at the start, 
expressed in per cent of the kiln-drj- weight: 

Table I. — Absorption of icater by dry loood. 



Air dried 

Kiln-dried 

In water 1 day . . . 
In water 2 days. . . 
In water 3 days. . 
In water 4 days.. 
In water 5 days.. 
In water 7 days.. 
In water 9 days... 
In water 11 days. 
In water 14 days. 
In water 17 days - 
In water 25 days. 
In water 30 days. 



White 
Pine. 


Red 
Cedar. 


Hem- 
lock. 


Tama- 
rack. 


lOS 


109 


Ill 


108 


100 


100 


100 


100 


13.5 


120 


133 


129 


147 


126 


144 


136 


\ai 


132 


149 


142 


162 


137 


154 


147 


165 


140 


158 


150 


176 


143 


164 


156 


179 


147 


168 


157 


184 


149 


173 


159 


187 


150 


176 


159 


■ 192 


152 


176 


161 


198 


155 


180 


161 


207 


158 


186 


166 



«See tables given by S. M. Rowe: The Preservation of Timber (souvenir edition). 
Chicago, 1900. 



WHAT SEASONING IS. 



11 



It will be noted that almost half of the increase in weight came dur- 
ing the iirst two days of soaking. The woods were kiln-dried after a 
long air seasoning. A similar test was made with pieces of the same 
woods which had not been kiln-dried; the only difference found was 
that they absorbed water more readily during the first few days. Fig. 
1 gives an indication of the rate at which air-dried wood will absorb 
water when submerged and lose it again when exposed to the air and 
sun. A number of absolutely air-dry blocks were kept submerged in 
water for five days. The gain in weight was noted from day to day. 









y 


















/ 


y 
















7 


y 








\ 










/ 










\ 


V 










^f^ 


.fj:::^-' 




\ 




\ 






/ / 


^ 




5;::^^'^ 






\ 






V 


t. 


^ 


\^^ 


•^^Y^ 






^ 




\ 






V 














■^^^ 




== 


s / 


2 


3 
















in 



Fig. 1. — Diagram showing absorption and loss of water by dry wood. 



After fire daj^s the same blocks were placed out of doors, exposed to 
sun and wind. The curves show the rate of absorption up to the sixth 
day, and the corresponding rate of loss thereafter. 

While this series of curves will, of coui'se, hold only for the par- 
ticular conditions under which this test was made, especiallj^ as 
i-egards drying, it nevertheless indicates how rapidly dry wood will 
absorb water and lose it again. It shows likewise that light, por- 
ous wood will absorb more water in a given period than heavier 
and denser wood. 



12 SEA80NINC4 OF TIMBER. 

V. SEASONING AND PRESEEVATIVE TREATMENT. 
SEASONING AND THE LEACHING OF SALTS. 

Where timber is chemically treated with salts dissolved in water, it 
will be absolutelj' necessary to season it after the treating process, for 
two reasons: First, to prevent the rapid leaching out of the salts 
pressed into the wood; second, to prevent subsequent decay. The 
practice, unfortunately in vogue in many cases, of placing timber 
treated with a water solution in positions where it comes in contact 
with water, can not be condemned too strongly. In the case of ties, 
the leaching out of salts takes place with startling rapidity when they 
are laid immediatelj^ after treatment. 

The manner in which salts soluble in water leach out, and the rela- 
tion of seasoning to this, is illustrated in a diagrammatic manner by 
figs. 2 to 6. Let us sujapose for the sake of illustration that a 
piece of nine wood is treated with a 20 Der cent solution of 



.r— -^ ) 


loz^ L_ 


1Q% ^]\ 


20 1 


-7 


20? 


1 ^^^^ 


20 ; 




'j^iL.. 


20* 


20? 


-^ 



tO 



Fig. 2. — Manner in which soluble salts leach out from treated timber. 

zinc chlorid. In consequence the cell openings are filled with this 
solution for some distance into the wood. Fig. 2 represents sev- 
eral series of wood cells, very much shortened for the sake of bringing 
them into the diagram. The dotted areas indicate water or watery 
solution of zinc chlorid. Let us assume that these cells are situated 
at the end of a tie, and that the ballast of sand touches them. The 
rounded masses marked .s represent the sand grains, with air spaces 
between them. Immediately after treatment the cells are filled with 
the 20 per cent solution of zinc chloxid, and the spaces between the bal- 
last particles are filled with air. Several days later a rain storm fills 
these air spaces with water. We then have pure water touching 
directly a 20 per cent solution of zinc chlori'd. It is a well-known law 
of solutions that solutions of different densities tend to mix until a 
solution of medium density is foi-med. Shortly after the rain storm, 
therefore, the 20 per cent solution of zinc chlorid in the outer wood 
cells will have been reduced, let us say, to a 10 per cent solution, and 



Bui. 41, Bureau of Forestry, U. S. Dept. of Agriculture. 





FiQ. 1.— Scotch Pine Ties Seasoning, Great 
Western Railway, England. 



FiQ. 2.— Piling Baltic Pine on the Great 
Western Railway, England. 




n 




B 


■k 


' > i 


H 




^ 


^^H^ ^^^irl 


fl 


B 


■^y^^i 


1 



Fig. 3.— Ties Arriving in Canal Boats, Great 
Western Railway, England. 



Fig. 4.— Another View of Fig. 2. 
PILING PINE ON THE GREAT WESTERN RAILWAY, ENGLAND. 



ul. 41, Bureau of Forestry, U. S. Dept. of AgricuUurs 




Fig. 1.— Tie Yard, Sheridan, Wyo., April, 1902— Solid Piles. 




Fig. 2.— Tie Yard, Sheridan, Wyo., September, 1902— Open Piles. 



SEASONING AND PBESERVATIVE TREATMENT. 13 

the pure water in the Ijallast has become a 10 i^er cent solution of zinc 
chlorid (fig. 3). There has been, in other words, a transfer of some of the 
zinc salt from the wood into the ballast. When the rain stops, all the 
water in the spaces between the sand o-rains runs off into the lower 
strata of the JDallast. Meanwhile a process of equalization has been 
going on among the various wood cells, which began as soon as some 
of the salt left the outermost cells. Fig. -i shows in a diagrammatic 



10% 



,.^^-^^^^^^ !0|. 

Fig. 3. — Manner in which soluble salts leach out from treated timber. 

way what this process is. Some of the zinc chlorid in the second tier 
of wood cells passes through the walls into the outermost cells, and 
this continues until the solutions in the two series are practicall}' of 
equal strength, i. e., about 15 per cent. In the same way the third 
tier of cells loses some of its salt to the second, the fourth to the third, 
and so on. This practically amounts to a gradual traveling of the zinc 
salt outward in the tie toward the end; The next rain storm will 



'¥''L 


rat 


10% — *- 


!Qi 


20Z 


10 o- 


'j^jiC. 


20% ^ ^ 


JO°Q — *■ 



20^ 


15% —^11 15% 


-0% 


IS% ^ 15% 


'~20%J^(~ 


" 15% --,| I5%1(' 


1 






Fig. 4. — Manner in which soluble salts leach out from treated timber. 

reduce the 15 per cent solution in the outer wood cells to a 7.5 per cent 
solution, which will again be strengthened from the mner cells. Thus 
the zinc chlorid gradually leaves the wood until none is left. This grad- 
ual traveling outward of the zinc chlorid goes on with varying rapidit}^ 
depending on the amount of water in the ballast, the frequency' with 
which the water is renewed, and its temperature. 

In the case of seasoned wood something ver}' ditt'erent takes place. 
When the wood dries the zinc salt is deposited in crystalline form in the 



14 SEASONIJS^G OF TIMBER. 

wood cells and walls as shown in fig. 5. When the rain water fills the 
spaces between the sand grains, as represented in fig. 6, it passes into the 
outer wood cells and dissolves some of the zinc salt there. This passes 
out just as it did in the first case, except that in this instance the water 
must first of all dissolve the zinc chlorid, which in the former instance 
was already in solution. Only a portion of the salt is thus dissolved. 
Moreover, the water does not penetrate very far, for the air in the cell 



O 



D 






Fig. 5. — Manner in which soluble salts .leaeli out from treated timber. 

cavities forms a considerable obstacle to its entrance. When the rain 
ceases the water in the outer cells evaporates, leaving some of the salt 
in the cells. After this evapoi'ation there is no transfer of zinc salt 
from the inner wood cells toward the outer cells. This is a matter of 
great importance, for it means that the salt injected remains for a much 
longer period in the seasoned than in the unseasoned wood. Subse- 
quent rain storms do not material^ change the conditions, for with 
every one only the outer cells are aot to have salt leached out from 
their cavities. 




Fig. 6.— Manner in which soluble '•alts leach oiit from treated timber 

The cells shown in figs. 2 to 6 might represent wood cells from any 
part of a tie. In practice the leaching out of salts usuallj' takes place 
first in the middle of the tie, and around the spike and under the rail 
or tie plates. The water collects in the spike holes or in any crack 



SEASONING AND PRESERVATIVE TREATMENT. 



15 



or check in the tie, aucl the conditions described are therebj' pro- 
duced. Ends of fibers are exposed in the spike hole and in every 
crack, or wherever the wood fibers are torn or broken. 

A crude test was made with several Lodgepole Pine ties for the 
purpose of giving at least a partial indication of the different rates at 
which zinc chlorid leaches out from treated ties with and without sea- 
soning after treatment. Two ties were taken — one which had dried 
for three months, the other fresh from the treating cylinder. The 
calculated amount of zinc chlorid in each was about 24 ounces. After 
twenty-four hours soaking it was found that the seasoned tie had lost 
3 ounces of zinc chlorid (calculated from the amount of zinc chlorid in 
the water), while the newly treated tie had lost 5.5 ounces, or almost 
twice as much. Stating these figures in another way, the seasoned tie 
had lost in twent3'-four hours about one-eighth of the salt injected, 
and the freshly treated tie about one-fourth of its salt. 

A test which gives more reliable figures was conducted as follows: 
A number of Lodgepole Pine ties were treated with zinc chlorid, and 
the amount of salt absorbed was determined by weighing the tie before 
and after treatment. The ties were then sawed in half. One-half of 
each tie was placed in water for twentj'-four hours, at the end of which 
period the amount of salt leached out was determined and the half ties 
allowed to dry for twenty-four hours, after which they were again 
submerged. This process was kept up for several days. The second 
half of each tie dried imtil air-dry, and was then alternately submerg;ed 
and dried just as the first halves had been, the amounts of salts leached 
out being determined after every leaching. The following table shows 
the results obtained: 

Table II. — Leaching of zinc chlorid. 
FRESHLY TREATED LODGEPOLE PINE (12 HALF TIES). 



Number of tie. 


Grains leached in 24-hour periods. 1 


First 
period. 


Second 
period. 


Third 
period. 


Fourth 
period. 


Fifth 
period. 


Sixth 
period. 


1 


720 
oOO 
600 
330 
375 
500 
370 

eso 

937 
630 
650 
735 


247 
378 
405 
324 
255 
255 
126 
2.50 
570 
307 
345 
360 


270 
210 
380 
323 
290 
360 
250 
350 
412 
290 
291 
250 


1.50 
187 
307 
140 
209 
437 
125 
212 
292 
210 
214 
236 


168 
120 
285 
210 
153 
405 
255 
210 
170 
159 
220 
107 


161 
131 
262 
187 
120 
310 
202 
237 
220 
225 
205 
157 




3 


4-.. 


0.. 






8 


9 

10 


11 

12 


Average . . . 


.585 


318 1 306 1 226 

1 i 


205 


201 



16 



SEKSONINa OF TIMBER. 

Table II. — Leaching of zinc chlorid — Continued. 

SEASONED LODGEPOLE PINE (12 HALF TIES). 



Number of tie. 




Grains leached in 24-hour periods. 




First 
period. 


Second 
period. 


Third 
period. 


Fourth 
period. 


Fifth 
period. 


Sixth 
period. 


1 

8 


555 
460 
439 
1,250 
620 
675 
512 
770 
805 
675 
800 
562 


600 
337 
365 
300 
157 
472 
350 


69 

127 
197 
212 
82 
236 
140 


92- 

67 
131 
150 

92 
147 

81 
105 
1.50 

90 
150 


125 
60 
100 
1.56 
120 
162 
137 
137 
86 
• 123 
150 
115 


62 
31 
45 
62 
57 
80 
57 
78 
87 
55 
92 
45 




5 






8 


332 , 200 
390 117 
260 ' 127 
405 2.50 
360 92 




10 

11 

12 

Average - . . 


677 


3.52 154 


109 122 


62 



It will be noted that the first two column.? show an even larger 
amount of leaching from the dry than from the seasoned ties. This 
was probablj^ due to numerous small checks caused by rapid drying, 
which exposed a larger surface to the action of the water. Later 
determinations, however, show a very marked falling off in the amount 
of leaching from the diy ties compared with the freshl}" treated ones. 
This is exactly what ought to have taken place according to the theory 
of leaching set forth above. The salt which leached out from the 
diy ties at first came from the outside of the wood. When it was 
removed the leaching was materiallj' reduced, because there was no 
chance for the salts within the tie to move toward the ' ■i^-'''?. These 
tables are still incomplete. Completed tables will be published in a 
succeeding bulletin. 

Attention is here called to the results obtained in seasoning Lodge- 
pole Pine ties after treatment, given on page 38. It will be suificieut 
to say at this point that ties treated in June, 1902, lost 2i to 26 per 
cent of their weight after seasoning three weeks. 

Lodgepole Pine fence posts, treated with zinc chlorid June 2. 1902, 
and then piled in an open pile to season, lost water in the next sixty- 
five days as shown in the table on the following page. 



Bui. 41, Bureau of Forestry, U. S. Depl. of Agriculluri 




Fig. 1.— Tie Chopper Making Two Straight Faces on the Stick. 




Fig. 2.— Peeling the Bark from the Lodqepole Pine. 
MAKING A TIE OUT OF LODGEPOLE PINE TIMBER. BOZEMAN, MONT 



Bui. 41, Bureau of Forestry, U. S. Dept. of Agriculture. 



K 


^WR^^^ 




f Z'-fll £ S^JS Mt -s^ H-H ftW^ ^ ' 


H 




ml- W^m 




Ni^^Ki^^' ^^^i 


1 




mm 




■HMm 




^SWSJ^i 


m 




v^^^Tw^^^ w^HR|^^^g<^^^^B^^^^^uK^9 


% 




•^s 
Ai 


i,i^^^^/'=^<J, 


w 


wsf i^rm 




1^^ im^^r^-i^-t^ 



Fig. 1 .— Lodqepole-Pine Forest with Tie Timber Cut Out. 




Fig. 2.— Cutting of Ties in the Woods. 



SEASONING AND PRESERVATIVE TREATMENT. 



17 



Table III. — Lodgepok Pine fence posts — Eiaporation of water after treatmetit u'itli, zinc 

chlorid. 
[Thirty-nine posts. Treated June 2, 1902.] 



Before treating 

1 hour after treating 

1 day after treating. . 
' 2 days after treating. 

3 days after treating. 

5 days after treating. 

7 days after treating. 
10 days after treating. 
15 days after treating. 
23 days after treating. 
31 days after treating. 
35 days after treating. 
42 days after treating. 
50 days after treating, 
55 days after treating. 
61 days after treating. 
65 days after treating. 



Weight of 
39 posts. 



4,660 
4,450 
4,325 
4,190 
4,0.55 
3,860 
3, 657 
3,488 
3,295 
3, 162 
3,072 
2,996 
2,900 
2,844 
2,780 
2,716 



Average 
weight per 
. post. 



^loss^/i'^in P"<^™t 



Pomuis. 
66. 03 
119.48 
114.10 
110.90 
107. 43 
103. 97 
98.97 
93.77 
89.43 
84.50 
81.08 



74.36 
72.92 
71.29 
69.64 



post. 



-15.51 
-20. 51 
-25.75 
-30. 05 
-34. 98 
-38. 40 
-40.71 
- 42. 66 
-45.12 
-46. 56 
-48. 19 
-49.48 



orloss( — ). 



+80.94 
-10. 06 
-16.05 
-22. 54 
-29. 02 
-36.37 
-48. 10 
-56. 22 
-65.44 
-71.83 
-76. 16 
-79. 81 
-84.41 
-87. 11 
-90. 16 



It will be seen that in the two months about 93 per cent of the water 
injected into the posts by the treatment evaporated, leaving practically 
dry zinc chlorid in the wood cells. Most of these posts were set in 
Nebraska and Wyoming, together with some untreated posts. Six are 
still piled and will be placed in the ground in a Southern State during 
the winter of 1902-3. 



SEASONING AND THE PROCESSES OF PRESERVATION. 

The cjuestion of the relation of the water content of timber to the 
various treating processes has so far received but little attention in 
this country. The subject is one of the greatest importance, for much 
of the ultimate success of most forms of timber treatment depends 
upon the amount of water in the wood before treatment. Mr. O. 
Chanute and others have repeatedly urged the absolute necessit}' for 
thorough seasoning of timber before treatment with zinc chlorid. 
The success of timber treatment depends upon a series of factors 
entirely apart from the mere impregnation of the wood with one sub- 
stance or another, and the sooner it is realized that the actual treat- 
ment is only one small part in the operations tending to obtain increased 
length of life, the better it will be. 

The object of timber treatment is to get certain chemical compounds 

into the wood with as much thoroughness as possible. Because of its 

peculiar structure, wood will not allow of the penetration of liquids into 

its mass as does a sponge. The solution must work its way into the 

19704— No. -41—03 2 



18 SEASOKING OF TIMBER, 

wood libers through walls of wood substance. If a water solution is 
used for the impregnating material, it ought to fill ever}" cell and per- 
meate every wall, at least in the sapwood. The most successful 
method for timber treatment (excepting the boiling process) so far 
used consists in pi-essing the solution into the wood. If the wood cells 
and the walls are already full of water, it is eas}^ to see that there will 
be great difficulty in making the water already in place give way to 
the solution. When walls and cell cavities are free from water the 
process of absorption of a solution is facilitated by the readiness with 
which the capillary forces operative in wood fiber aid the absorption. 
Nor is this all. Seasoning not onlj* brings about a reduction in the 
amount of water, but also results in the partial disintegration of the 
albuminous substances which ofi^er more or less . resistance to the 
entrance of solutions. The steaming of wood before the injection of 
the solution can never replace seasoning as a means of preparation for 
treatment, for at best it does no more than drive off part of the water. 

When the substance used is ordinary creosote or tar oil, the matter 
of seasoning is still more important. At the present time there are 
several plants in operation where green or watersoaked wood is steamed 
in a cylinder for var3dng lengths of time and then treated with tar oil, 
which is I'un in after the formation of a vacuum. The I'eason given 
for this method of operation is that just as efiective a penetration of 
the tar oil is secured at a lower cost, since the timber does not have to 
be held until it is seasoned. An extended discussion of this subject 
is reserved for another report. It is enough to say now that tar oil and 
water do not mix, and that a porous medium entirely or partially filled 
with water will not become so thoroughh' penetrated as one which is 
dr}'. T>ry wood fiber absorbs tar oil with great readiness, as anyone 
can prove who will pour tar oil into the ends of two pieces of wood, 
one drj' and one moist. To the claim frequently made that wood 
when steamed is absolute^ dry, one may answer that such is indeed 
true when the temperature is raised sufficiently high to reach to the 
very center of the piece of wood treated, but such temperatures are 
frequently so high that the wood fiber itself is materially injured. 

The experience of the European railroads and other consumers of 
treated timbers is so ver^^ conclusive that it seems almost needless to 
contend for a careful seasoning of timber before treatment. The great 
objection made against it is the time required. The risk taken when 
timber is held, as well as the interest on the investment, is sometimes 
considerable; but it is believed that the tests already made and those 
in progress will serve to show that in the long run the saving from 
better service far exceeds the cost. 

Another consideration of decided hnportmce is the time required for 
the treatment. No definite data are yet at hand which will admit of a 
fair comparison, but it is a matter of experience that the length of time 
necessary to treat seasoned wood with an}' of the ordinary preserva- 



ADVANTAGES OF SEASONING. 19 

tives is very much shorter than foi' unseasoned. (Careful tests are now 
in progress with Lodgepole Pine, and similar tests will be made with 
other timbers this 3-ear. 

If, therefore, we take into consideration the greater thoroughness 
with which timber can be treated after ample seasoning, as well as the 
larger amount which can be treated in a given time, it would appear 
that any treatment which does not accuratelj' specif}' that all wood 
must be thoroughly seasoned befoi'e treatment with zinc chlorid, tar 
oil, or both, or any combination which contains salts, should be regarded 
with disfavor. It is claimed for several processes, notably for the 
Hasselmann and the electrical treatments, that green wood can be 
treated as well as seasoned wood. Should this prove true, the objec- 
tions made to the ordinary methods of treatment would not apply to 
them. 

VI. ADVANTAGES OF SEASONING. 

Two most important advantages of seasoning have already been made 
apparent: 

(1) Seasoned timber lasts umch longer than unseasoned. Since the 
decay of timber is due to the attacks of wood-destroying fungi, and 
since the most impoi'tant condition of the growth of these fungi is 
water, anything which lessens the amount of water in wood aids in its 
preservation. 

(2) In the case of treated timber, seasoning before treatment greatlj' 
increases the effectiveness of the ordinary methods of treatment, and 
seasoning after treatment prevents the rapid leaching out of salts 
introdv;ced to preserve the timber. 

Additional advantages of seasoning are: 

SAVING IN FREIGHT. 

Few persons realize how much water green wood contains, or how 
much it will lose in a comparatively short time. Experiments along 
this line with Lodgepole Pine, White Oak, and Chestnut gave results 
which were a surprise, not onlj- to the companies owning the timber, 
but also to the writer. Freight charges vary much in different parts 
of the country ; but a decrease of 35 to 40 per cent in weight is impor- 
tant enough to deserve everj'where serious consideration from those 
in charge of timber operations. When timber is shipped long dis- 
tances over several roads, as is coming to be more and more the case, 
the saving in freight will make a material difference in the cost of 
ties, bridge materials, etc., irrespective of an}^ other advantages of 
seasoning. 

USE OF CHEAP TIMBERS. 

One of the questions which is engaging the attention of all large 
consumers of timber is the possibility of substituting low-grade tim- 
bers for those of a higher grade now in use. High and low grade are 



20 ■ S2AS0NING OB" TIMBER. 

of course relative terms; a timber which is called low grade to-day 
maj- a few j'ears hence be classed as high grade. Such a change has 
taken place in the past in the case of White Oak. From the point of 
view of the railroads the question of high or low grade is primarily a 
question of the durability, or "length of life," of difl'erent kinds of 
timber for their particular needs — as ties, fence posts, and telegraph 
and telephone poles. This, however, is complicated by the efiect on 
prices of the general market demand. The price for a hewn White Oak 
tie in southern Illinois, delivered on the right of way, is 35 cents. But 
White Oak timber will bring twice this price, and frequently more, 
for boards, staves, etc. This discrepancy in prices is bound to increase 
with the increasing use of White Oak timber in the form of lumber, 
and ^vith increasing scarcity. It is very obvious that it is a poor 
business policj^ for anyone owning timber to sell it for ties when he 
can get more for it in the form of lumber. Consequently the railroads 
niust pa}' more and more for their ties, or find a substitute for "^Miite 
Oak in some cheaper material. In former years an investment of 
from 20 to 30 cents was amply repaid by the five to seven years" serv- 
ice ordinariljr obtained from White Oak ties in the North. Such 
service will not pay for an investment of 50 to 75 cents. It is very 
evident to most railroad men that some change will have to be brought 
about, and in fact such a change is actually taking place now. 

A further consideration lies in the interest of other industries which 
depend on a constant supply of White Oak. The manufacturer of 
tight barrels, for instance, must have White Oak, and can not substi • 
tute the porous Red Oak. If the railroads continue to use White Oak 
for ties, they are cutting off a supply which will seriously affect such 
industries. If White Oak were the only available material for ties, 
this consideration would have no weight; but such is not the case. 
In the regions which now contribute most largely to the White Oak 
supply, a number of infei'ior oaks are found in even greater abun- 
dance, and it will probably be only a short time before most railroad 
companies will learn that these timbers can be used just as well as 
White Oak. In a number of recent contracts, lumber contractors 
have been allowed *the option of furnishing Eed Oak " properly 
treated " in place of White Oak. 

The same facts hold true for other classes of timber. During the 
past year the Lodgepole Pine of the Northwest has been substituted 
for the higher grade Bull Pine. It is believed that the time is not 
far distant when the Longleaf Pine will no longer be used for ties, 
particularly in Mississippi, Louisiana, and Texas, for its value in the 
form of lumber is already so high that any marked increase will 
bring about a situation very much like that which now obtains in the 
case of White Oak. The Shortleaf and Loblolly pines will then find a 
use for which they can be prepared at a cost low enough to permit of 
their economical emplojauent. 



41, Bureau of Forestry, U. S. Dept of Agncul;i 




FiQ. 1.— Dragging Ties to the Flume. 




Fig. 2.— Tie Piles at the Flume. 



3ul. 41, Bureau of Forestry, V. S. Dept, of Agricutturt 




Fig. 1.— Throwing Ties into the Flume. 




Fig. 2.— Ties Ready for the Flume. 



ul 41, Bureau of Forestry, U. S. Dept. of Agriculture. 




FiQ. 2.— Another View of Flume. 



u[. 41, Bureau of Forestry, U. S. Dept. ot Agricutturc 




Fig. 1,— End of Flume at Railroad Track. 




Fig. 2.— Another View of Same. 



ADVANTAGES OF SEASONING. 



21 



One of the lirst questions to arise when we consider the substitution 
of Red and Swamp Oak for White Oak, Loblollj- Pine for Long-leaf 
Pine, or Hemlock and Tamarack for oak and pine, is. What shall be 
done to these timbers so as to get the maximum value out of the 
investment? The crux of the situation is the comparative lasting 
powers of the various timbers. That which applies to ties holds true 
also for telephone and telegraph poles, fence posts, bridge material, 
etc.; in short, for all timbers which are exjDosed to deca3\ It is 
believed that, b}' proper treatment, timbers which otherwise could 
not be used for the purposes specified above can be made to serve 
longer than the uuti'eated timbers in use up to the present time. 



loo 


■^— 


— 




— 


— 


-"■ 




— . 




— 







■ 


' 














"~~ 


~~ 





" 


— 


—^ 












































































































































































So 

r 












































































































































































































































































































































































































































































































































































n' '^^ 








































































































f 








































































































































































































































































































































/ 




































































































































































r' 


































































































































































































































































































































































































































































































































































^<>- 


































































































































































































































































































































































































































* 


























































































































































































































-^ 


































































































-^; 
























— 


— 




— 


— 


-^ 


-^ 


— - 


i^ 


:^ 




=^ 


S 


S 




-^ 




— 


— 


























3 4 5 c T © 3 »o 11 la 13 w 15 »c VT la >3 ao ai 2^^ 23 -ZA T.G 

-Diagram showing lengtti of life of oak and beech ties, French Eastern Railway. 



The relative ease with which so-called high and low grade timbers 
can be treated is another matter requiring consideration. As a rule, 
high-grade timbers — Longleaf Pine or White Oak, for instance — are 
very much denser than the lower grades, sixch as Loblolly Pine or 
Red Oak. The latter generally have a higher percentage of sapwood, 
which can be peneti'ated b}^ a treating iiuid verj' much more readily 
than heartwood. On account of this greater porosity it is very much 
more economical to treat a porous wood thoroughly with a good pre- 
servative than to treat a more expensive denser wood with a cheaper 
preservative. The cheap and porous wood well treated will outlast 
the other in every instance. Fig. T shows this graphically. The 
short-lived, porous Beech, which ordinarily lasts but four to five 



'^2 SEASONITSTG OF TIMBEE. 

years, has outlasted the Oak several times over. It would be a 
great waste, therefore, to attempt the treatment of White Oak or Long- 
leaf Pine when better results will be obtained by using Loblolly Pine 
or Red Oak. 

One of the tirst steps in the process of making short-lived timbers 
fit for treatment consists in a proper seasoning. More benefit will 
result from taking care of the short-lived timbers than from similar 
treatment of those with longer life. The former are frequently short 
lived because of their greater porosity, which may mean a higher water 
content, and which always means a greater power of absorbing and 
holding water. The economical substitution of cheap for high-priced 
timbers is impossible without proper seasoning. The loss from the 
shortened term of service of unseasoned timber is very, much greater in 
the case of porous than of the denser kinds, which are much less per- 
meable by water, and consequenth^ offer greater resistance to decaj'. 
Susceptibility to decay in timber is a consequence both of relatively high 
porosity, which may mean a high water content, and always means a 
greater absorptive power, and of a large percentage of sapwood, which 
furnishes, by its stores of organic matter, food for wood-destroying 
fungi. Seasoning greatlj^ lengthens its life, because it rids it as far as 
possible of its water and brings about a disintegration of much of the 
organic matter, in both ways lessening the chances for destruction of 
the wood by its fungus enemies. Seasoning is therefore of the first 
importance for the utilization of cheap timbers hitherto regarded as 
short-lived. 

PREVENTION OF CHECKING AND SPLITTING. 

Under present methods much timber is rendered unfit for use by 
improper seasoning. PI. Ill furnishes a good example of this. Green 
timber, particularlj^ when cut in the fall or winter, contains a large 
amount of water. When exposed to the sun and wind the water will 
evaporate more rapidly from the outer than from the inner parts of 
a log, and more rapidly from the ends than from the sides. As the 
water evaporates, the wood shrinks, and when the shiinkage is not 
fairly uniform the wood cracks. When wet wood is piled in the sun, 
as were the ties and timbers shown on PI. Ill, evaporation goes on 
with such unevenness that the timbers split and crack so badly as to 
become absolutely useless. Such uneven dicing can be prevented by 
careful piling. A very large number of ties and timbers split from 
this cause are thrown out of use every year, and it is time that more 
attention were given to prevent this waste. 

In Europe many railroads use S irons, which are driven into the 
ends of timbers in danger of splitting, and effect a great saving. 
Fig. 8 shows such an iron," and tig. 9 its manner of application. 

« Eeprinted from Bull. 14, Bureau of Plant Industry, U. S. Department of Agricul- 
ture, 1902. 



ADVANTAGES OF SEASONING. 



23 



Len&tm of piece. =■ 5.13 



es t^*^ 





jj:^ o.o's* 



-H ;♦- 0.076 



LeiS&TH OF PIECE. = €>.S 




^'.7 3 



a.-^'S. 



,<>.A7 





DIA11-6.S9 



->Jf- 0.039 







-^u. o.o'ss 



1 



Fig. 8. — " S " irons used to prevent checking 



Dl>^^1= 1.16 




Fig. 9.— Method of applying "S" irons to pre- 
vent checking. 



24 



SEASONING OF TIMBER. 



VI. HOW TIMBER IS SEASONED. 
KILX DRYING. 

As kiln drying is emploj'ed mostly to prevent the warping and 
checking of wood, and only rarely to prevent decay, it is not necessarj' 
to dwell at length upon this method of seasoning. In the Southern 
States it is often used to prevent the development of the blue fungus 
during the sjM'ing, when the percentage of moisture in the air is very 
great. 

SEASONING IN OTHEK COUNTKIES. 

Seasoning of timber has been carried on in a practical way for manj^ 
years in Europe. Most of the European railroads season their ties 
for many months before they treat them. The tie piles of the Great 




Fig. 10. — Pile of ties on Freneti Eastern Railway. (Reprint from Bull. 14, Bureau of Plant Industry, 
U.S. Department of Agriculture, 1902. ) 

Western Kailway of England (PI. IV) are a novel sight to the Ameri- 
can obsei'ver. The ties are piled by means of a donkey engine, and 
remain in piles for from five to twelve months. The Baltic Pine used 
hy this road is very moist when it arrives; but in the high, open piles 
it dries out very rapidly, and when finally seasoned it absorbs in a few 
hours the tar oil with which it is treated. The French Eastern Rail- 
way piles its ties in open piles (fig. 10) 3.50 meters (11.4 feet) high, 
2.7 meters (8.8 feet) wide, and 2.7 to 20 meters (8.8 to 65.6 feet) long. 
The piles are 1.5 meters (about 5 feet) apart. The ties are spaced with 
intervals of IM meter (1 inches) between ties, except that the top tiers 
are inclined, as shown in the figure, to shed rain water. At Amagne 
some 400,000 untreated and treated ties can be placed. Oak ties are 
allowed to remain in jailes for from fifteen to twenty months; Beech 
ties, six months. The French engineers assert that a good uniform 



ul. 41, Bureau of Forestry. U. S. Dept. of Agriculh 




Fig. 1.— Landing Platform, Bozeman, Mont. 




Fig. 2. -Another View of Landing Platform. 



Bui. 41, Bureau of Forestry, U. S Dept. of Agriculture. 




Fig. 1.— Lodgepole Pine— Solid Pile. 





<^^L^:^ - ^j 










L^I^-^^^iP-^^ 


I^J^ 


set 


--...^i^^sdneL 1 


*^;®***. ^*f^:,^ 




fin^^ 


^^i^s^^m 




m^ -«*... m. ■ ,M 


^^^ 


*^ . :^.- '^t^S^^ff^^BI 




■S^HkP^SHb^^-^^k 


■Bi^^—i-j- ' 


Oi 


MPin§ 






^(I^S 


S0 


^.^7 11 




^^^H^^^^BL'. jt*^"^ '-- '^- ji^iEI^M 


^^ji^ - --ajuiii 


i^ 


K^MJ 



FiQ. 2.— Lodgepole Pine— Half-open Pile. 



HOW TIMBER IS SEASONED. 



25 



treatment with tai- oil can not be obtained even with air-dry ties, which 
thej' therefore drj' in a kihi before treatment for from sixty to eight}' 
hours at a temperature beginning at 35° C. and gradually brought to 
75° C. A complete description of the method of kiln-drjdng will be 
found in the Appendix. 

The following table shows the importance of kiln-drying to secure 
the most perfect removal of water: 

Table IV. — Loasi of weight by out-of-door seasoning and kiln drying — French Eastern 
Railway. 



Kind of tim))( 



Aver.age -weight per tii 



After a 
ing. 



Average weight per cubic 
meter. 



After ai] 
season- 
ing. 



After 

kiln 

drying. 



Loss in weight in 

per cent of 
original weight. 



After air 
season- 
ing. 



Oak (IS months airdry- 
ing: 14i hours in dry 
kiln; size of tie, 0.09 
cubic meters), 

Beech (6 months air 
drying; 72 hours in 
dry kiln; size of tie, 
0.097 cubic meters) . . . 



It appears from this table that the kiln drying removes 3 to 4 per 
cent additional water from the wood after the out-of-door seasoning. 

Fui-ther advantages of the French method of kiln drying are speci- 
fied as follows: 

But the kiln drying is not, only for the purpose of completing the open-air season- 
ing. It also assures a perfectly uniform preparation at all seasons of the j'ear, and 
sometimes with woods M'hich could not be left long enough to dry in the yards. 
Further, as the kiln-dried woods are hot when they enter the cylinders, the heavy 
oil which comes into contact with them there, is kept alwaj's fluid and at a nearly 
even temperature, and consequently penetrates them so much the deeper. « 

Fig. 11 shows the average variation in weight per cubic meter, i. e., 
the specific gravity', from month to month, as determined hj engineers 
of the French Eastern Railway. The ties were piled as described, dur- 
ing the winter, from two to three months after being cut. 

The practice on other European roads differs considerably with the 
kind of timber used and the time of felling. In some cases, as in that 
of the Hungarian State Railways, the bark is stripped from newly 
felled trees and the trunks stacked in the woods for one to two years: 
other roads stack only three or four months. New Zealand railroads 



"Note sur la preparation des traverses it la compagnie des ehemins de fer de I'Est. 
M. \. Dufaux. Extract from Rev. Generale d. Chemins de Fer., Jan. and Mar., 
1898, p. 19. 



26 



SEASONING OK TIMBER. 



reijort no stacking at all. In Australia the Australian Southern Rail- 
road specifies that wood cut in winter must have its bark removed, 
while that cut in summer can at once be cut up. 

The loss of weight by evaporation in Hungar}- is shown b}^ the 
following quotation: 

The Austro-Hungarian State Railway has observed that wood when felled contains 
40 per cent of water; five months subsequently it contains about 30 to 35 per cent; 
and after it has been stored a year it contains about 20 to 25 per cent. (International 
Railway Congress. Question VIII, p. 11. Paris, 1900.) 







U 


1 


< 




3 


S 


3 

3 


I 

p. 


© 


1 




After— 


1 
§ 


t 1 ■ 

5 i 


100 
CSS 
C.90 
OSS 
























































































































































































































































, 
















































































— -1 


\ 


V 




























\ 


\ 






























\v 
























1 




































■ 


\ 






















\ 








\ 






















1 








V ■■ 






















, 








\ 




























































\ 






















1 








> 




N 






















1 





\. 




=f^ 










, 









__!_ 


, ^ 


H 


— 


— \ 






— 1. 




:;; — 


— 









— 




— 
















"^ 


" 


*^ 


y 




. 






























\ 






























\ 












\ 


















\ 


' 1 










* 




















1 




C.'S 
C-70 








•3^ 


\ 




























•J?K~ 


















1 












c-^ 














































































1 





















_- 


— 


,--■" 


"v 




I 


























■*% 
































\ 


1 




























^^ 


1 




























*^ 










































































■ 





















































































Fig. 11. — Diagram showing average loss in weight by seasoning of oak 
and beech timber during one year. French Eastern Railway. 



In Russia oak ties are stacked from three to six months. Treatment 
sometimes follows and sometimes not, some lines having found that 
the increased length of life of a thoroughly seasoned oak tie treated 
with zinc chlorid does not pay for the additional cost. Their oak is 
so superior to our best American oaks that their practice affords no 
criterion for us. 



HOW TIMBER IS SEASONED. 27 

In general, all railroad ties, bridge materials, telegraph poles, fence 
posts, etc., are commonly seasoned in Europe, and to some extent in 
other countries. The time of seasoning varies from several months to 
two years. 

SEASONING BT STEAMING. 

Where time is so important as it is in business affairs to-day, it is 
often a serious matter to hold timber for from four to six months 
before using it. In addition to the loss of interest on the capital 
invested there is also constant danger from fire. Any method by 
which timber could be seasoned rapidly and economically would be of 
great value. Reference has been already made to the use of live 
steam for this purpose. In a number of timber-treating plants in this 
countrj^ green or water-soaked wood is steamed for several hours to 
prepare it for the injection of chemicals. Steaming is also used to 
some extent with material for furniture manufacture. Steaming is 
said to coagulate the albuminous substances present in wood, thus 
rendering the walls of the wood fibers more permeable. That such is 
its effect there can be no doubt, for these coagulated albuminous sub- 
stances make up a large proportion of the solid parts of the so-called 
"sap" which remains in the retorts after steaming. This "sap "is 
water driven out of the wood by the expansion of the air within it and 
by the entering water vapor, and it holds in solution and suspension 
the albuminous substances referred to, various tannin bodies, resins, 
oils, etc. Steamed wood certainly ought to last longer than unsteamed, 
and where it is necessary to secure partiallj' seasoned wood the steam- 
ing may do. It is, however, at best a makeshift, and unless modified, 
materially it can never replace open-air seasoning, supplemented pos- 
sibly by kiln-drying. There is danger of injury to the wood fibers 
from too high a temperature. There ma}^ be absolutely' no harm in 
prolonged steaming at high temperature, but in the present incom- 
plete state of our knowledge it is better to be on the safe side. It has 
been pointed out that the steaming process after all does not remove 
all water unless the temperature is very high. The use of the vacuum 
pump does not materially improve matters, for it is not possible to 
maintain a sufficiently high temperature in a cylinder in which enough 
of a vacuum exists to insure the complete removal of all water. 

A recent publication refers to the extensive use of steam seasoning 
in Australia. No details, however, have as yet been obtainable. 

SEASONING BY IMMERSION IN WATER. 

It is an old saying that wood put into water shortly after it is 
felled, and left in water for a j'ear or more, will be perfectly seasoned 
after a short subsequent exposure to the air. For this reason river 



28 SEASONING OF TIMBER. 

men maintain that timbei- is made better by i-aftiug. Herzenstein 

says:" 

Floating the timber down rivers helps to wash out the sap, and hence must be 
considered as favorable to its preservation, the more so as it enables it to absorb 
more preservative. 

Wood which has been buried in swamps is eagerly sought after b}' 
carpenters and joiners, because it has lost all tendency to warp and 
twist. When first taken from the swamp the long-immersed logs are 
very much heavier than water, but they dry with great rapidity. A 
Cypress log from the Mississipx^i Delta, which two men could barely 
handle at the time it was taken out some j-ears ago, has dried out so 
much since then that to-daj' one man can lift it with ease. White 
Cedar telephone and telegraph poles are said to remain floating in the 
water of the Great Lakes sometimes for several years before the}' are 
set in lines and to last better than freshly cut poles. 

It is very probable that immersion for long periods in water does 
materially hasten subsequent seasoning. The tannins, resins, albu- 
minous materials, etc., which are deposited in the cell walls of the 
fibers of green wood, and which prevent rapid evaporation of the 
water, undergo changes when under water, probably due to the action 
of bacteria which can live without air, and in the course of time many 
of these substances are leached out of the wood. The cells thereby 
become more and more permeable to water, and when the wood is 
finally brought into the air the water escapes very rapidly and very 
evenly. Herzenstein's statement that wood prepared by immersion 
and subsequent drying will absorb more preservative, and that with 
.greater rapidity, is certainly borne out by experience in this country. 

SEASONING BY BOILING IN OIL. 

It is sometimes claimed that all seasoning preparatory to ti-eatmeut 
with a substance like tar oil might be done awaj' with by putting the 
green wood into a cylinder with the oil and heating to 225- F.. thus 
driving the water ofl" in the form of steam, after which the tar oil 
would readily penetrate into the wood. This is the basis of the 
so-called ' ' Curtiss process ' ' of timber treatment. Without going into 
any discussion of this method of creosoting, it may be said that the 
same objection made for steaming holds here. In order to get a tem- 
perature of 212° F. in the center of the treated wood the outside 
temperature would have to be raised so high that the strength of the 
wood might be seriously injured. 

A compan}' on the Pacific coast which treats Red Fir piling asserts 
that it avoids this danger by leaving the green timber in the tar oil at 
a temperature which never exceeds 225^ F. for from five to twelve 
hours, until there is no further evidence of water vapor coming out of 

"Bull. Internat. Railway Congress. Question VIII. Paris, 1900, p. 10. 



PLATSr FOE SEASONING TESTS. 29 

the wood. The tar oil is then run out, and a vacuum is created for 
about an hour, after which the oil is run in again and is kept in the 
c^'linders under 100 pounds pressure for from ten to twelve hours, 
until the required amount of absorption has been reached (about 12 
pounds per cubic foot). 

OUT- OF-DOOE SEASONING. 

The most effective seasoning is without doubt that obtained by the 
uniform, slow drj'ing which takes place in properly constructed jailes 
outdoors, under exposure to the winds and the sun. Lumber has 
always been seasoned in this wa}', which is still the best and cheapest 
for ordinary purposes. The methods in use have been determined by 
long experience, and are probably as good as they could be made for 
present conditions. But the same care has not up to this time been 
given to the seasoning of such classes of timber as ties, bridge material, 
posts, telegraph and telephone poles, etc. These have sometimes been 
piled more or less intelligently, but in the majority of cases their value 
has been too low to make it seem worth while to pile with reference 
to anything beyond convenience in handling. A discussion as to pos- 
sible methods is given in the following chapters. 

VIII. PLAN FOE, SEASONING TESTS. 

In the foregoing chapters an attempt has been made to present a 
general view of the seasoning of timber — what it is, how it works, and 
what its advantages are. Although the general facts are a matter of 
common knowledge, there are scarcel}' any exact data in existence 
concerning some of the most important phases of the subject. This is 
particularly true of timber in the form of railroad ties and telephone 
and telegraph poles. The tirst step necessary toward working out 
the most practical and economical methods of using timber for test 
purposes must be a careful stud}^ of all the processes involved in sea- 
soning. To this end a series of tests on a uniform plan has been 
inaugurated, applicable both to the kinds of timber now in use and to 
kinds which may come into use in the future. It ought to be empha- 
sized, however, that to secure reliable data it will be necessary to carry 
on these tests for a number of years, with a large number of ijieces of 
many different kinds of timber, and in different parts of the country. 
The reason for this is thatthevariabilitj'in the physical characteristics 
of timber, even of the same kind, is so great that figm-es obtained 
from a small number of pieces are very apt to be entirely unreliable. 
A glance at some of the figures in the tables given below will show 
this. In the case of different kinds of timber, or of different timbers 
of the same kind grown under different climatic conditions or seasoned 
in different years, the same thing is true in still greater degree. 

In determining the amount of seasoning, some standard of measure- 
ment had to be taken. As the loss in weight due to the evaporation 



30 SEASONING OF TIMBER. 

of water forms the largest part of the seasoning- process, it was decided 
to adopt the test of the loss of weight as furnishing the nearest 
approach to an absolute register of the degree of seasoning which can 
be given numerical expression. 

The specific questions which it is proposed to investigate in the 
series of seasoning tests which has been inaugurated are: 

(1) The variation in character and weight of wood, and in the rat§ 
at which the wood loses water, among trees of the same species grown 
under the same conditions and of the same age — that is. individual 
variation in seasoning. 

(2) The variation in the water content of the same timber in difiereut 
months, and the length of time necessary to dr}' it properly at dif- 
ferent seasons — that is, seasonal variation in seasoning. This inquiry 
will have the important result that it will settle the question of the 
best time to cut timber. 

(3) The variation in the amount of water in difi'erent parts of the 
same tree, or regional variation. Top wood is generally believed not 
to be so good as butt wood, and much of it is therefore rejected. 
Ties and posts from the tops and bottoms of a large number of trees 
will be tested to determine the amounts of water in both parts, and 
the rate at which thej- will season. 

(4) The effect of bark on seasoning. Although it is universally 
known that bark will retard and almost prevent seasoning, un barked 
ties and piles are nevertheless sometimes used. A test will be made 
to show exactly to what extent this shortens the length of life of 
timber. 

(5) The rate of seasoning of sawed, hewn, and planed timber. At 
present more hewn than sawed timber is in use ; but as sawing is 
cheaper, it is probable that this condition will soon be reversed. ItJs 
important to know whether there is any material difference in the rate 
of seasoning between sawed and hewn timber. The saw cuts many 
wood fibei-s so as to expose their open ends, and it is conceivable that 
the rate of water evaporation maj- be influenced somewhat by this fact. 
Then again, the rough surface of sawed timber may retard evapora- 
tion. It is therefore proposed to compare the rate with that of planed 
timbei'. 

(6) Great practical value is expected to attach to a series of experi- 
ments intended to answer the question how ties, poles, and other 
timbers should be piled to season them in the shortest possible time. 

(7) Getting timber into immediate use counts for so much nowadays 
that it is verj' important to know just how long treated timber must be 
held to secure the thorough drying on which much of the efficacv of 
treatment depends. It is proposed to make accurate tests in various 
parts of the country to determine the shortest period during which 
treated timber should be held, and what method or methods of piling 
will bring about the most rapid results. 



SEASONING TESTS WITH LODGEPOLE PINE. 81 

IX. SEASONING TESTS WITH LODGEPOLE PINE. 

Lodgepole Pine {Pinus murraijana) is one of a number of inferior 
timbers growing in the Northwest which are coming into use. This 
tree is found in large quantities in the mountains of Wj'oming, Mon- 
tana, and northern Idaho. It is very tall and slender. Its diameter 
4 feet above the ground does not average more than li inches, and 
rarely exceeds 20 inches. At an altitude of about 6,000 feet, where it 
reaches its best development, it has a remarkabh- long, straight trunk, 
with a very slight taper. This characteristic makes it a good tree for 
ties. In the futui'e it ma}'' be used also for telephone and telegraph 
poles. 

The wood of Lodgepole Pine contains a very large percentage of 
sapwood. It is light, soft, and straight grained, and can be worked 
easily. In drying it checks badh', even when the drying is slow, but 
the checks are small and rareh' extend far into the wood. "The 
specific gi'avity of absolutelv dry wood is 0.4096, a cubic foot weigh- 
ing 25.53 pounds."" The wood contains a large percentage of water. 
It is a very short-lived timber, and for this reason has been but little 
used until lately. 

TESTS AT BOZEilAN, MONT. 

In April, 1902, experiments were begun in cooperation with the 
Burlington and Missouri River Railroad in Nebraska, and with Mr. 
Walter Cooper, of Bozeman, Mont., to determine whether it would 
paj' to season Lodgepole Pine timber. It was believed that with 
proper care and treatment Lodgepole Pine could be made to last 
almost as long as Bull Pine timber, and certainly longer than has 
hitherto been supposed. The experiments are still in progress, and 
will be continued until sufficient data have been obtained to warrant 
definite conclusions. A description of the tests is given below. It is 
preceded by an account of how the ties are made, since a knowledge 
of these operations is essential to a complete understanding of what 
happens to the timber afterwards. 

MAKING AXD DELIVERY OP TIES. 

The forest fi-om which the ties were cut grows on a range of moun- 
tains at the east end of the Gallatin Valley in Montana, at an elevation 
of about 6,500 feet. Most of the timber cut stood in a basin at the 
head of Bear Creek, near Bozeman, and was a fair stand of Lodge- 
pole Pine as it grows in Montana and Idaho. (PL VII.) 

From three to five pole ties are obtained from a single tree under 14 
inches in diameter, breasthigh. Many of the trees are fire scarred at 
the base, causing a brown rot to set in which makes it necessary to cut 
off butt logs from 4 to 10 feet in length. Trees larger than 14 inches 
in diameter, breasthigh, are usually cut into logs, which are trans- 

" Sargent, C. S., in Silva of North America, XI, 93, 1897. 



32 SEASONING OF TIMBER. 

ported to sawmills, of which there are two in operation on the tract 
where the test ties were cut. The ties are mostly hewn, 8 feet long, 
6 inches thick, and with two 8-inch hewn faces. In order to get 
a tie of these dimensions, the chopper must have a stick of timber 
at least 9 inches in diameter at the small end. Much larger ties are 
often cut, some reaching a width of from 13 to 14 inches at one end. 
As soon as the tree is felled, the chopper, standing on the timber, 
makes two straight faces (PI. VI, fig. 1); he then cuts the tree into 
8-foot lengths, allowing .3 inches for the cut. Finall}' the ties are 
peeled with a tie peeler. (PI. VI, fig. 2.) A skillful man can make 
from 4:0 to 50 ties per day in good timber. After the ties are made 
they usualljr remain in the woods for several weeks before thej' are 
dragged out with chains (PI. VIII, fig. 1). or skidded out on go-devils , 
to the flume, where they are piled, readj"^ for shipment (PL VIII, fig. 2, 
and PI. IX). 

The ties used in the seasoning tests were taken indiscriminately 
from the general run of ties in the woods. The onh* difference made 
in handling them was in skidding them out immediately after cutting, 
before there was anj^ chance for them to dry. On arriving at the 
flume each tie was numbered and weighed. 

The timber land operated on in the summer of 1902 is about 9 miles 
from the railroad track and about 1,800 feet above it. Early in the 
year a flume was built (Pis. IX and X), extending through the timber 
to the railroad, where a landing was constructed, reached by a siding 
from the main line (Pis. XI and XII). The flume is about 9 miles long, 
with an average fall of 200 feet per mile. The water used for float- 
ing the timber is obtained from a creek and from a storage reservoir. 

It was suggested that drying the ties in the woods would be useless, 
since they were to be put into the flume afterwards, where they would 
absorb as much water as they had lost. A test was therefore made to 
learn how much water dry ties would absorb. A number of ties cut 
sixty days before, and fairly well seasoned, showed an average weight 
of 116.61 pounds per tie. To float the 9 miles required about forty- 
eight minutes. At the end of their journey the average weight was 
■117.41 pounds, a total gain per tie of only 0.8 pound. Ties in the 
same seasoned state as these, after immersion in a stream for one 
hour, showed a gain in weight of 2 per cent, but two hours after they 
were taken from the water they had returned to their original weight. 
The tests showed that the amount of water absorbed in the fluming 
process may be disregarded. 

The ties are inspected at the landing, and are then shipped to the 
timber-treating plant at Sheridan, AVj-o. 

PILIXG OF TIES. 

Piling tests were made with Lodgepole Pine to learn exactly the 
rate of water evaporation from the ties under varjnng conditions and at 



ul. 41. Bureau of Foreslry, U. S. Dept of Agriculli 




Fig. 1.— Before Treatment. 




Fig. 2.— After Treatment. 
LODGEPOLE PINE, OPEN-CRIB PILE. 



, 41, Bureau of Forestry, U. S. Dept. of Agriculturf 




Fig. 1 .—Triangular Tie Piles. 




Fig. 2.— Lodqepole Pine Piled to Test Influence of Prevailing Winds on Drying. 



Bui. 41, Bureau of Forestry, U, S, Dept. of AE;ricu!ture, 




FiQ. 1.— Oak Pili ■,, ,Sh<',vj,, L<-.vi si Tier on the Ground— a Poor Method. 




Fig. 2.— Oak Piles, Showing Lowest Tier on the Ground— a Poor Method. 



SEASONING TESTS WITH LODGEPOLE PINE. 33 

different seasons of the year. Ties placed in piles of different forms 
were weighed every two weeks, and the results tabulated. Although 
timber is known to dr}^ most rapidly when exposed on all sides to the 
sun and air, close piling was tried as well as open, to show the difference 
in the length of time required for seasoning and in the rate at which 
water is lost. In all the piles the lowest laj^er rested on two bottom 
ties. About 50 ties went into each pile, and the piles were reversed 
at each weighing, the top ties of the old pile going to the bottom of 
the new. 

The forms of piles were: 

(1) A solid pile, 9 ties each way with no space between. (PI. XIII, 
fig. 1.) This method of piling has been largelj^ in vogue, and is still 
used to some extent by man)^ railroads in this country. It affords 
very little chance for the circulation of air. 

(2) A half-open pile, in which the ties were piled 7 each waj^, with 
about 4 inches left between. (PI. XIII, fig. 2.) 

(3) An open pile, or open-crib pile, in which the air circulated freely 
on all sides of the ties, which were piled in alternate layers, 7 one 
way and 2 the other. (PL XIV.) The piles at Bozeman were built 
to such a height that men could easilj' place the ties in position from 
the ground. At Sheridan, Wyo., it was possible to build much higher 
open piles (Pis. I and V) because the ties were unloaded from cars. 
Plate XIV, figs. 1 and 2, show in addition to the open crib method of 
piling the difference in color between treated and untreated timber. 
Treatment darkens the color so much that it is possible to distinguish 
at a glance between the two. 

(4) Treated ties were piled also in a form which gives even more 
air and sun exposure (PL XV, fig. 1), viz, a triangular pile, so con- 
structed that no two ties touched at more than one point, and no tie 
rested entirelj^ on the ground. Where there is plenty of room, as 
there generally is along the right of way, this form of pile is more 
rapidly made than the others. 

In the diagrams the various forms of piles are designated as follows: 
I. Solid pile, 9 by 9 ties. 
II. Half-open pile, 7 by 7 ties. 

III. Open-crib pile, 7 by 2 ties. 

IV. Triangular pile. 

WIND DIRECTION. 

To test the possible influence of prevailing winds, the open faces of 
some of the piles were built facing east and west, and of others north 
and south. (PL XV, fig. 2.) One point never lost sight of was to find 
a method of piling which would give the most rapid results at the least 
cost. A discussion of the results obtained is presented on p. S-t. 

INTERVALS OF CUTTINGS. 

As one of the objects of the seasoning tests was to determine the 
monthly variation in the water content of timber, arrangements were 
19704— No. 41—03 3 



34 



SEASONING OF TIMBER. 



made to test ties cut at intervals of one month. This is still going on. 
About 100 ties are taken- ever}^ month and piled in the open-crib form, 
which gives the most rapid results. 

PRELIMINARY RESULTS OF SEASONING TESTS. 

The following tables present the results of the tests made with 
Lodgepole Pine timber for the first five months. Although it is per- 
haps too early to draw definite conclusions, it is believed that the data 
already obtained have sufficient significance to justify their publica- 
tion now. They are arranged in two series, of which the first gives 
the weights of water lost in pounds and in percentages of the original 
weights of the ties; the second, the loss in weight in terms of specific 
gravity. A graphical presentation of this second series is given by 
curves (fig. 12), which will be extended when the weighing tests have 
been carried on for another six months. 

Table V presents the results of tests made with ties which had been 
in solid piles in the j^ards at Sheridan for about two months. After 
the first weighing these ties were piled in three difl:erent wa3's — 9 by 9, 
7 by 7, and 7 by 2. The table shows the rate at which they lost weight 
subsequently. 

Table "V. — Rate of evaporation from partially seasoned ties, Lodgepole Pine, 
Sheridan, Wyo. 



Date of weigh- 
ing. 


Solid pile, 9 by 9 (60 ties). 


Half-open pile, 7 by 7 (65 
ties). 


Open-crib pile, 7 by 2 (60 
ties). 


Weight 
per tie. 


Loss per 
tie. 


Per 

cent of 

loss. 


Weight 
per tie. 


Loss per 
tie. 


Per 

cent of 

loss. 


Weight 
per tie. 


Loss per 
tie 


Per 

cent of 

losg. 




Pounds. 
111.93 
109 

107.15 
105.05 
102.97 
103.42 


Founds. 




Pounds. 
96.80 
94.10 

. 92. 52 
90.75 
89.11 
89.61 


Pounds. 




Pounds. 
112. 90 
109. 43 
107.66 
105.47 
103.27 
103.68 


Pounds. 






2.93 
4.78 
S.8S 
8.96 
8.51 


2.61 

4.27 

6.14 

8 

7.60 


2.70 
4.28 
6.50 
7.69 
7.19 


2.80 
4.42 
6.25 
7.94 
7.43 


3.47 
5.34 
7.43 
9.63 
9.22 


3.07 




4.73 


August 11 

September 11... 
October 10 


6.68 
8.53 
8.21 



These ties were almost dry when piled; nevertheless they lost con- 
siderablj^ more water in the open-crib pile than in the solid pile. 

One factor which was not anticipated when the weighing tests were 
started must be taken into consideration in all the preliminaiy figures 
here presented. The experimental solid piles were placed out on the 
open plain, and as a result of the consequent free circulation of air 
the rate of drying was much more rapid than it would have been in a 
yard. When solid piles are placed side bj^ .side and many together, 
the air can not circulate between the timbers. In all future tests 
conditions will be more nearlj^ like the actual conditions in a tie j'ard. 
The open-crib piles allow full air circulation even when piled closely, 
so that the rate of drying shown for such test piles is probably more 
nearly correct. 



SEASONING TESTS WITH LODGEPOLE PINE. 

Table VI. — Rate of seasoning of Lodgepole Pine, green ties. 



35 





Solid pile (50 ties). 


Open-crib pile (50 ties). 


Date of weighing. 


Weight 
per tie. 


Loss per 
tie. 


Per cent 
of loss. 


Weight 
per tie. 


Loss per 
tie. 


Per cent 
of loss. 


June 9 


Pounds. 
152. 75 
130. 93 
114. 77 
104. 24 
101.33 


Pounds. 




Pounds. 
155. 39 
108. 06 
99.30 
95.71 
93.44 


Pounds. 






21.82 
37.98 
48.51 
61.42 


14. 2S 
24.86 
31.75 
33.66 


47.33 
56.09 
59.68 
61.95 


30.45 
36.09 
38.46 
39.86 


July 15 












JUNE JULY AUC SEPT. 

Fig. 12. — Diagram showing rate of drying of green ties. 

Table VI .shows the rate of diying of green ties, piled in solid and 
open-crib piles. The results are regarded as sufficiently marked to 
warrant recommending the use of the open-crib pile whenever possible. 
The curves in fig. 13 are a graphic presentation of the figures given in 
Table VI. 

A study of these figures and curves show.s that after three weeks 
the ties piled in open-crib form lost more than twice as much water 
as those in the solid pile. The great advantage which the open-crib 
form has over the other is the rapidity with which seasoning takes 
place during the first few weeks. It is probable that the relative 



36 



SEASONING- OF TIMBER. 



positions of the curves of loss will be changed slightly when more tim- 
bers are weighed, but the general result will not be altered materially. 

SEASONING AFTER TREATMENT WITH ZINC CHLORID. 

Timber treated with a water solution of a salt is, like green timber, 
full of water. The results of a test to show the comparative rate of 
diying of treated Lodgepole Pine timber piled in the several forms of 
piles made at Sheridan are shown in Table VII and fig. 13. The first 
weighing was made the day after treatment. 

Table VII. — Rate of seasoning of Lodgepole Pine ties treated witJi zinc chlorid. 





Solid pile, 9 by 9 
(60 ties). 


Half-open pile, 7 bv7 
(59 ties). 


Open-crib pile, 7 by 2 
(60 ties). 


Triangular pile (33 
ties). 


weigliiiig. 


Weight 
per tie. 


Loss 
pertie. 


Per 
cent of 

loss. 


Weight 
pertie. 


Loss 
pertie. 


Per 
cent of 
loss. 


Weight 
per tie. 


Loss 
pertie. 


Per 
cent 6f 
loss. 


Weight 
per tie. 


Loss 
pertie. 


Per 
cent of 
loss. 




Lbs. 


lbs. 




Lbs. 


Lbs. 




Lbs. 


Lbs. 




Lbs. 


Lbs. 




June 17.... 
July 11-... 














172 10 






105. 94 






123. 13 


40.74 


24.86 


127. 80 


46.64 


26.16 


122.80 


49.30 


28.64 


118.66 


47.28 


28.49 


July 25.... 


114.43 


49.43 


30.16 


119.30 


55.14 


31.03 


115.27 


56.83 


33.02 


111.73 


54.21 


32.67 


Aug. 11.... 


108.60 


55.36 


33.78 


112.84 


61.60 


35. 31 


109. 70 


62.40 


36.25 


106. 54 


59.40 


35.85 


Aug. 25.... 


105. 67 


58.19 


35.51 


110. 04 


64.40 


36.92 


106.80 


65.30 


37.94 


103.58 


62.36 


37.58 


Sept. 25.... 


103. 43 


60.43 


36.89 


107. 40 


67.04 


38.43 


104. SO 


67.80 


39.40 


102.33. 


63.61 


38.33 


Oct. 25...- 


102.36 


61.59 


37.54 


106. 05 


68.39 


39.20 


102. ,86 


69.24 


40.23 


100.03 


65.91 


39.66 













































































_I- 
















r^sS 


^ 


^ 


U= 









=3 








73. 


_J 
















^ 


^ 

































y 


^ 


r 














Ti- 
ll - 




> f' 


HM f 










Hav-1 


L o. 






7/ 


/ 
















I - 

n - 


Ops 
Tri. 




MB F 


Pll_ 


- 










/ 


































i 






































/ 






































/ 







































Fig. 13.— Diagram showing rate of seasoning of Lodgepole Pine ties treated with zinc chlorid. 

The chief conclusions to be drawn from this test are that on the open 
plains in summer there is little difierence in the rate of evaporation 
from the differently built piles, and that in all of them most of the 
water evaporates during the first si.x; weeks. Accordingly, ties left for 



SEASONING TESTS WITH LODGEPOLE PINE. 



37 



six to eight weeks along the right of waj^ may be laid in the track at 
the end of that time. This conclusion will hold as j^et only for ^¥3^0- 
ming and for the summer months. Great emphasis is to be put upon 
this point, for it is more than probable that in other climates this rela- 
tion will be verjr different. A test under the most adverse conditions 
is now in progress in southern Texas, where timber dries very slowly. 

INDIVIDUAL VARIATION IN SEASONING. 

The striking difference between pieces of timber from different trees 
of the same kind, even when grown in the same locality', is nowhere 
shown more conclusively than in the amount of water contained in the 
wood and the rate at which it evaporates. This great variability empha- 
sizes the necessity for extended tests. Averages made from small 
numbers of weighings are likely to be altogether misleading, and ought 
never to be taken as a basis for any final conclusion. It is to be under- 
stood that all the figures given in the tables of this bulletin are merely 
tentative and subject to modification as fuller results become available. 

The ties whose weights are shown in Table VIII and fig. 1-t were cut 
in June, 1902, at Bozeman, Mont. They were first weighed June 2.5, 
the daj^ after they were made. Table VIII gives the successive weights 
per tie, the actual loss in %lo; 
weight, and the percent- 
age of the original weight 
lost. Fig. 14 shows the 
loss in weight of ties Nos. 
26, 13, and 33, represent- 
ing a mean and two ex- 
tremes. The great vari- 
ation shown is probably 
due to the fact that the 
ties came from trees of 
different ages and from 
both tops and butts. To 
see the great extremes 
between which 50 pieces 
will vary, one need only 
glance at the following 
figures, showing weights 
of 50 ties arranged in a 
series from the lowest to 
the highest. It is evi- 
dent from this showing 
that the variation in 50 
pieces is so large that a very much larger number of individual weights 
should be taken to furnish data for thoroughly trustwortlw conclu- 
sions. Further tests are being made with from 200 to 500 pieces. 





















Y^ie. 


H. 












^ 


^ 
















f 


/ 




















/ 




















1 










— ■ 




MC 


P,r». 






1 


/ 


^ 
















/ 


/ 


/ 


















// 


1 














U 


oWi^ 


1 


'I 


^ 




— 














I 


V 




















/ 























-Diagram showing loss of weight of 3 tie 
and two extremes. 



38 



SEASONING OF TIMBER. 



Table VIII. — Lodyepole Pine ties, Bozeman, Mont., 1902. 
[Ties piled 7 by 2.] 



Tie No. 


June 25. 


July 10. 


August 10. 


September 10. 1 


Weight. 


Weight. 


Loss. 


Per 
cent of 
loss. 


Weight. 


Loss. 


Per 

cent of 

loss. 


Weight. 


! Per 
Loss, cent of 
1 loss. 




Pounds. 


Pounds. 


Vounds. 




Pounds. 


Pounds. 




Pounds. 


Pounds. 


1 


211. b 


185.5 


42.0 


18.46 


129.5 


98.0 


43.08 


126.0 


101.5 


44.61 


2 


202.5 


175.0 


27.5 


13.58 


125.5 


77.0 


38.02 


118.0 


84.5 


41.73 


3 


182.0 


146.5 


35.5 


19.50 


100.0 


82.0 


45.05 


95.0 


87.0 


47.80 


4 


147.0 


125.5 


21.5 


14.62 


113.0 


34.0 


23.13 


110.5 


36.5 


24.89 


5 


211.0 


172.0 


39.0 


18.48 


130.0 


81.0 


38.39 


120.5 


90.5 


42.75 


6 


162.0 


130.0 


32.0 


19.76 


108.0 


54.0 


33.33 


105.5 


66.5 


34.87 


7 


203.0 


166.5 


36.5 


17.98 


156.0 


47.0 


23.15 


151.5 


61.5 


25.13 


8 


132.5 


110.0 


22.5 


16.98 


100.5 


32.0 


24.16 


99.0 


33.5 


26.28 


9 


190.5 


159 5 


31.0 


16.27 


148.0 


42.5 


22.30 


145.0 


45.5 


23.88 


10 


154.0 


110.5 


43.5 


28.24 


88.0 


66.0 


42.85 


8B.0 


58.0 


37.66 


11 


174.0 


133.0 


41.0 


23.56 


93.6 


80.5 


46.29 


90.5 


83.5 


47.99 


12 


164.0 


133.0 


31.0 


18.90 


95.5 


68.5 


4L79 


9L0 


73.0 


44.61 


13 


154.0 


126.5 


27.5 


17.86 


106.0 


48.0 


31.17 


102.5 


.51.5 


33.44 


14 


146.0 


110.5 


35.5 


24.31 


94,0 


52.0 


35.61 


91.5 


54.5 


37.33 


15 


139.5 


102.0 


37.5 


26.88 


93.0 


46.6 


33.33 


90.5 


49.0 


35.12 


16 


146.5 


96.5 


50.0 


34.13 


67.5 


79.0 


53.92 


64.5 


82.0 


55.97 


17 


148.5 


118.5 


30.0 


20.20 


106.0 


42.5 


28.61 


104.0 


44.5 


30.00 


18 


151.5 


125.6 


26.0 


17.22 


110.0 


41.5 


27.39 


108.0 


43.6 


28.71 


19 


176.5 


130.5 


46.0 


26.06 


100:0 


76.5 


43.34 


97.0 


79.5 


45.04 


20 


165.0 


129.0 


36.0 


21.81 


115.0 


50.0 


33.33 


112.0 


53.0 


32.12 


21 


120.5 


105.0 


15.5 


12.86 


101.0 


19.5 


16.17 


98.5 


22.0 


18.25 


22 


156.0 


113.5 


42.5 


27.24 


90.5 


65.5 


41.98 


88.0 


68.0 


43. ,59 


23 


146.5 


117.0 


29.5 


20.13 


87.0 


59.5 


40.61 


84.5 


62.0 


42.32 


24 


149.0 


106.0 


43.0 


28.85 


96.0 


53.0 


35.56 


93.6 


55.5 


37.25 


25 


181.0 


161.0 


20.0 


11.04 


154.0 


27.0 


14.91 


151.0 


30.0 


16,57 


26 


13S.0 


99.5 


33.5 


25.20 


88.5 


44.5 


23.44 


86.0 


47.0 


35.34 


27 


128.0 


92.0 


36.0 


28.12 


80.0 


48.0 


37.47 


77.0 


51.0 


39.84 


28 


184.0 


132.5 


51.5 


27.98 


90.0 


94.0 


51.08 


84.5 


99.5 


54.07 


29 


134.0 


103.5 


30.5 


22.74 


84.5 


49.5 


36.92 


82.0 


52.0 


38.80 


30 


135.5 


98.5 


37.0 


27.28 


72.0 


63.5 


46.80 


70.0 


65.6 


48.34 


31 


193.0 


153.0 


40.0 


20.72 


111.0 


82.0 


42.50 


105.5 


87.5 


4.5.34 


32 


162.0 


129.5 


32.5 


20.04 


101.5 


60.5 


37.32 


■ 97.5 


64.5 


39.81 


33 


187.0 


139.0 


48.0 


25.66 


96.0 


91.0 


48.60 


91.5 


95.5 


61.07 


34 


126.0 


89.0 


37.0 


29.38 


79.0 


47.0 


37.28 


77.5 


48.5 


38.49 


35 


159.0 


117.5 


31.5 


19.80 


96.0 


63.0 


39.60 


93.5 


66.5 


41.19 


36 


154.5 


121.0 


33.6 


21.64 


112.5 


42.0 


27.17 


110.0 


44.6 


28.80 


37 


177.0 


156.0 


21.0 


11.87 


144.0 


33.0 


18.63 


140.0 


37.0 


20.90 


38 


154.5 


120.5 


34.0 


22.00 


111.0 


43.5 


28.16 


108.0 


. 46.5 


30.09 


39 


133.0 


105.0 


, 28.0 


21.05 


96.5 


36.5 


27.43 


94.0 


39.0 


29.32 


40 


182.5 


134.5 


48.0 


20.86 


116.5 


66.0 


36.18 


113.5 


69.0 


37. 80 


41 


87.5 


83.5 


4.0 


4. .57 


80.0 


7.5 


8.57 


78.0 


9.5 


10.86 


42 


194.5 


142.0 


52.5 


27.00 


122.0 


72.5 


37.21 


119.0 


75.5 


38.81 


43 


141.0 


102.5 


38.5 


27.30 


90.5 


50.6 


35.80 


89.5 


61.5 


36.52 


44 


168.5 


118.0 


50.5 


29.98 


108.0 


60.5 


3.5.90 


105.5 


63.0 


37.39 


45 


132.5 


106.0 


26.5 


20.00 


100.0 


32.6 


24.54 


97.0 


35.5 


26.71 


46 


97.5 


70.0 


27.5 


28.22 


66.6 


31.0 


31.80 


64.6 


33.0 


33.84 


47 


130.5 


82.0 


48.6 


' 27. 17 


74.5 


56.0 


42.83 


71.5 


59.0 


45.21 


48 


147.0 


108.0 


39.0 


26.52 


92.5 


55.6 


37.72 


89.5 


57.5 


39.11 


49 


90.0 


84. 


6.0 


6.67 


81.0 


9.0 


10.00 


79.0 


11.0 


12.22 


50 

Aver- 


126.0 


106.5 


19.5 


15.47 


102.0 


24.0 


19.05 


100.0 


26.0 


20.63 






























21. 40 






33.78 






35,54 



















SEASONING TESTS WITH LODGEPOLE PINE. 



39 



VARIATION BY MONTHS. 

It has been shown in a genei'al waj' that timber will season more 
slowly in winter than in summer, and also that the water content dur- 
ing various months varies, but no detinite data are as yet at hand. To 
secure .such data for Lodgepole Pine the series of tests of ties cut 
monthly, already? described, was inaugurated. Later on these ties will 
be treated, and the relation between seasonal cutting and timber treat- 
ment determined. The relation between seasonal cutting and lasting- 
powers will also be investigated. 

In Table IX the results so far obtained with ties cut in June, July, 
August, and September, of 1902, are given in the form of general 
averages. The piles were 7 lyy 2, and were reversed from top to 
bottom at each weighing. 

Table IX. — Lodgex>ole Pine, Bozeinan, Mont, 1902. 
JUNE CUTTING. 



Date of weighing. 


No. of 
ties. 


Weight 
per tie. 


Loss in 
pounds. 


Percent- 
age loss. 


1902. 


147 
147 
147 
147 


156.62 
123.22 
103.72 
100.66 






July 10 ... 


33.40 
52.90 
55.96 


21.30 
33.77 
36.73 




September 10 



JULY CUTTING. 



July 20 ; 

July 25 ;. 

.August 8 

August 28 

September 10 . 



270 
90 


144. 28 
129.90 






14.34 


9.94 


270 


108.99 


35.29 


24.46 


90 


105.08 


39.16 


27.15 


270 


103.23 


41.05 


28.26 



AUGUST CUTTING. 



August 25 

September 10 . 
September 25 . 

October 25 

November 25 . 



100 
100 


149.83 
119.91 






29.92 


19.96 


100 


115. 35 


34.48 


23.01 


100 


113.21 


36.62 


24.44 


100 


114.02 


35.81 


23.90 



SEPTEMBER CUTTING. 



September 25 
October 5 . . . 
October 25... 
November 25 



100 
100 


157.33 
153.02 






4.31 


2.74 


100 


125, 04 


32. 29 


20.52 


100 


120.31' 


37.02 


23.53 



It is yet too early to draw any definite conclusions from these tables. 
They indicate, however, a decided variation in the weight of green ties 



40 



seasojS^ing of timber. 



cut in diflferent months, and a still more striking variatioai in the 
rapidity with which seasoning takes place in summer and in fall. 

Fig. 15 shows graphicalljr the loss of water in percentages of the 
original weights. Although the curves are plotted with but four or 
five points, they are fairly correct. 

The great deviation of the September curve requires explanation. 
Just after the ties had been cut and weighed there was a heavj" snow- 
fall, which covered the ties for a week or more. During this time 
they did not dry out at all. As soon as the snow melted thej- began 
to dry rapidly, as shown bj^ the sudden rise in the curve. The dotted 
line indicates the path which the curve would have followed had no 
disturbing factor caused a deviation from the norm of the other 
months. 






Fig. 15. — Diagram showing percentage loss of water of Lodgepole Pine timber during various months, 
Bozeman, Mont., 1902. 

In the spring the drying out of timber cut in October and Novem- 
ber will take place more rajjidlj^, and the depressed curves will prob- 
abh' rise to the same height as the first curve. 

Fig. 16 shows the changes in specific gravitj^ of the same timber. 
The specific gravity of absolute!}' dr}' Lodgepole Pine is 0.109, so that 
the June-cut timber has almost reached a dry condition (0.446). 

COST OF PILING. 



The practicability of piling in open-crib form depends entirely on 
the additional cost. Careful records kept at the Sheridan tie plant 
showed that it takes no longer to pile ties in open-crib form than in 
solid piles. The men who did the piling were paid by the laiece, so it 
was possible to keep an exact record. All that is called for is a little 



Bui. 41, Bureau of Forestry, U. S. Dept. of Agriculturs 



Plate XVII. 




Fig 1.— Oak Piles, Showing Method of Building a Roof. 







Fig. 2.— Another Method of Roof Building. 



Plate XVlll. 



tV' 


^^^^^^^^QplHfl^^HIHl 


'^0rf^^'^^ 


.^^^^j^BB JB|^B f/^^f ' K^' l^T * 


1^^^^ 


mm -j^n'TJMI qijigjg^ ^'-w^^mSm 


■%^ \ _ "^ 


:.i i^-^t-*i§"™J 


■^•,.K 


*i#-^^ : 



Fig. 1.— Open-crib Oak Pile, Southern Illinois. 




Fig. 2.— Another Open-crib Pile. 



SEASONING TESTS WITH LODGEPOLE PINE. 



41 



more care. The only difference in cost is the increased yard room 
necessary. Where land is cheap, this will not amount to much; where 
a treating plant is in the neighborhood of a cit}', it will be necessary 
to build high piles, or to use half -open piles. The amount of yard 
room for storing both untreated and treated ties ought to be one of 
the most important considerations in determining the location of a 
timber treating plant. Timber piled in high open piles (PI. I) can be 
loaded upon the small cars which carry the ties into the treating cyl- 



g 


June 30. 
July 31. 
September 30. 
October 31. 
November 30. 
December 31. 


1.00 
OSS 
•so 
.85 
■ 80 
.IS 

. 70 

.ss 

.60 
.55 
.50 
• 45 
-40 
.35 
. 50 
.25 
.20 
. IS 
. 10 
.05 






























































































^ 






\ 










^^ 




\ 


\ 


\ 




N^ 








\ \ 




\ 


^v^ 








V 


^ 


^-^ 




' 






















































































































































Fig. 16. — Diagram showing specific gravity of Lodgepole Pine timber cut during successive months. 

inder with as much ease as from high solid piles. The timbers must 
be thi'own down in both cases, and in this respect there is no diiler- 
ence between open and solid piles. 

Experience shows beyond doubt that open piling pays with Lodge- 
pole Pine. It will probably pay also in the case of oaks and other 
timbers which are to be treated, for, even with expensive storage land, 
the gain from better treatment will be great enough to warrant the 
expense. 



42 



SEASONING OF TIMBEE. 



X. SEASONING OF OAK TIMBER. 

For several months seasoning- experiments with White Oak timber 
have been under way, in cooperation with the Baltimore and Ohio 
Southwestern Eailroad, at various points in southern Illinois, Indiana, 
and Ohio. The plan of these tests was the same as that for Lodgepole 
Pine. Oak ties were obtained as soon as possible after they were cut 
from the tree. These, were piled in various ways, as shown in Pis. 
XVI to XVIII. Particular attention is called to the two piles shown 
on PI. XVI, illustrating- a method still too frequently employed, by 
which green ties are piled with the lowest tier of ties resting directljr 
on the ground. In the upper figure this lowest tier is almost buried 
in the weeds and grass, and it is evident that these ties have little or 
no chance to dry out. The better method of using two ties to support 
the lowest tier is shown in the piles on Pis. XVII and XVIII. 

The two forms of piles shown on PI. XVIII give the most air. Thej^ 
do not difi'er materially excejjt as to the spacing. PI. XVII represents 
an experiment made to test whether it would be possible to use the 
method commonly employed in France, of making the uppermost tier 
serve as a roof. The ties are placed close together, and are given a 
slope by placing a tie under one end. The lower figure shows a 
double roof, with the ties so placed that the upper tier covers the 
spaces in the lower tier. In a region where the annual rainfall is high, 
it is very probable that the seasoning of the whole pile will advance 
more rapidl}^ when the ties are in this form than in a pile not covered. 
The top tier can always dry out rapidly, even when wet, as it is so 
exposed to the sun and air. During the very heavy rains in the 
middle of December the ties under such a roof remained almost 
entirely dry. 

Some preliminary results of experiments with White Oak ties which 
had been cut for some time, showing the rate at which seasoning is 
taking place in the difl:erent forms of piles, are presented in the fol- 
lowing table. Onlj^ the first and last weights are given, with the aver- 
age loss per tie and the percentage of loss. These weighings were 
conducted at Fairfield, 111., on the Baltimore and Ohio Southwestern 
Railroad. The differences, though not as great as they would have 
been had the ties been green, are sufficiently striking to warrant 
advocating the open form of piling. 

Table X. — Preliminary weights of White Oak. 
OPEN-CRIB PILE, 7 BY 2. 



Date of weighing. 


Number 
of ties. 


Weight 
per tie. 


Loss per 
tie. 


Per cent 
of loss. 




75 
75 


Pounds. 
166. 47 
148.13 


Pounds. 




October 27 


18.34 


11.02 





TESTS WITH TELEPHONE POLES. 

Table X. — Preliminary loeiglUs of While Oak — Continued. 
HALF-OPEN PILE. 



43 



Date of weighing. 


Number 
of ties. 


Weight 
per tie. 


Loss per 
tie. 


Per cent 
of loss. 




101 
101 


155.62 
147. .=15 








8.27 


5.31 






SOLID PILE. 


A 


8.5 
85 


175.81 
166.91 








8.87 


5.04 





In about two and a half months the open pile lost more than twice 
as much as the solid pile. There was no additional cost in building- 
these White Oak piles in the same manner as the Lodgepole Pine. 
Eventually there may be a small increased cost of handling, but the 
gain outweighs the cost many times. 

XI. TESTS WITH TELEPHONE POLES. 

Tests have been made from time to time in this country to determine 
the practicability of preserving telephone and telegraph poles. Vari- 
ous preservatives have been applied to the whole poles, and in one 
instance methods of butt treatment were tried. The results have not 
always been satisfactoiy, particularly when creosote or tar oil have 
been used. This in most cases was no doubt due to the use of poor 
methods and a poor quality of creosote. 

Economical treatment of telephone or telegraph poles is veiy much 
more difficult than of ties or bridge timbers. The latter are exposed 
to decaying influences throughout their whole mass, while a pole is 
generally liable to rot only around the point where it enters the ground. 
Except in such climates as southern Texas and Louisiana, therefore, 
where timber exposed to the air rots rapidly, treatment of the whole 
pole is a great waste. Then again, ties and timbers can be taken 
without great cost to and from some central jireserving plant. This 
is frequently impossible with poles, especially when they are obtained 
locall}'; the freight charges would be so great that it would be 
cheaper to get new poles. In Europe, however, where the first cost 
of poles is very great, and where treated poles last twenty-five to 
thirty years, it paj'S to treat the whole pole. Those treated with tar 
oil in 1871 for the Prussian postal service are still in use in a line 
north of Berlin, and in good condition. The Swiss Government treats 
its poles with copper sulphate, after the old Boucherie process. 

With the increased cost of poles in this country, it has become a 
matter of considei'able moment to find some efficient and economical 
method of lengthening their lasting power. To this end some tests 



44 SEASONING OF TIMBEE. 

were started during the past summer. Before describing them it may 
be well to consider how poles give out, and what the conditions are 
which favor their decay. 

DECAY OF POLES. 

Poles set in the ground usually deca}^ at or or just below the surface 
of the ground. The reason for this will be plain when one remembers 
that two of the conditions necessary for the growth of the wood- 
destroying fungi are air and water. Above the ground the poles drj^ 
out in a short time, and remain dry; they therefore rarely decay in 
this part." Below the surface of the ground there is so little oxygen 
that the fungi can not grow; hence this part also does not rot readily. 
Poles standing in water are in the same class with those in the ground. 
Below the surface of the water no rot takes place because of the 
absence of air. Decay is at the surface of the water or a little above. 
The same thing is true of piles. The reason why poles give out first 
at or just below the surface is that both air and water are found there 
in sufficient quantities to permit the wood-destroying fungi to grow. 

PTAXS FOR PREVENTING DECAY OF POLES. 

As has been pointed out above, decaj' can be prevented either by 
keeping the wood dry or by chemical treatment. In the case of poles, 
if one can keep the butt dry the length of life of the pole will be con- 
siderablj' extended. The ease with which this can be done will vary 
with the soil conditions. In a heavy clay, where water stands for 
daj^s, it will be more difficult to establish drainage than in a sandy 
soil. In experimenting with pole treatment two lines of work have 
been started, one in seasoning poles, the other in treating the butts 
of poles. In the present bulletin we are concerned onlj' with the 
seasoning tests. These have been going on since July near Mount 
Arlington, N. J., in cooperation with the American Telephone and 
Teleg'raph Company. Chestnut poles are being cut in northern New 
Jersey for a long-distance line from Providence, K. I., to Philadelphia, 
and from these fifty 30-foot poles are taken every month for the sea- 
soning experiment. They are weighed one or two daj^s after thej^ are 
cut, and are then piled on a side hill, two poles on the ground and the 
remainder across them. An air space of about 16 to 20 inches is thus 
left under the pile. The poles are weighed every month. Incidentallj^ 
careful measurements of the circumference are made at three points. 
It is yet too early to give a,nj definite account of results, but the poles 
cut in August had lost 6.98 per cent of their first weight by October 28. 

While the average loss per pole in weight has not been very great 

f- An exception to this must be made for regions where during spring and summer 
the air holds enough moisture to keep the tops ^\et. AVhere this is the case the top 
will decay likewise. 



PLANS FOE FUTURE WORK. 45 

SO far, it must be remembered that the summer just past was a very 
wet one in New Jersej', and that the rate of evapoi'ation was influenced 
considerabh" thereby. The weighing of the separate lots is to be con- 
tinued until the poles have reached an air-cLy condition. Poles are to 
be cut every month throughout the year, so that figures correspond- 
ing to the weights obtained from ties will be available. The seasoned 
poles will be set in some line together with unseasoned poles, to deter- 
mine the difference in length of life. All poles are marked with nails 
indicating the month and j'ear during which they were cut. 

Similar seasoning tests for poles in other parts of the countrj- have 
been arranged for, and will be started as soon as possible. 

XII. PLANS FOR FUTURE "WORK.« 

Arrangements are pi'actically complete for carrying on further 
seasoning tests, as follows: 

SEASONING OF OAK TIMBEES. 

Two series of tests have been arranged to determine the compara- 
tive rate of seasoning and the best methods to season various kinds of 
oak. The tests will be mainlj' of White Oak, Ked Oak, Abater Oak, 
Black Oak, and such other oaks as occur in anj^ quantity in the 
Mississippi Valle3\ They are made in cooperation with the St. Louis 
and San Francisco Eailroad Company at several points in southwest 
Missouri and northwest Arkansas, and with the Illinois Central Eail- 
road Company and the Ayer & Lord Tie Company at several points 
in northern Mississippi, western Kentucky, and Tennessee. The 
tests with the Baltimore and Ohio Southwestern are being continued 
and will be enlarged. 

A determination of the length of time required for thorough spason- 
ing- is most necessary for successful chemical treatment of the inferior 
oak timbers. 

SEASONING OF PINE IN THE SOUTHERN STATES. 

In the Southern States it is difficult to keep green timber in the 
woods or in piles for any length of time, because of the rapidit}' with 
which wood-destro^'ing fungi attack it, particularly during warm 
weather. It may prove that the piling methods found so successful 
in the North will not give satisfactory results in the South, and that 
some form of kiln drying may have to be resorted to in order to get 
seasoned timber for treatment. An extensive experiment has been 
started in southern Texas, in cooperation with the Santa Fe Eailroad 
and the Kirbj- Lumber Company, for the purpose of testing (among 
other things) the rate of seasoning of ties. Two kinds of pine are to be 
tried, the Lobloll3' and the Shortleaf. Both sawed and hewn ties are to 
be used, and the experiment is to be as exhaustive as that in progress 

"April 15, 1903: The tests with oak and Southern pine have now been in operation 
three months. 



46 SEASONING OF TIMBER. 

with Lodgepole Pine. A similar experiment will be made in Arizona 
with the Mountain Pine, and another in northern Georgia and South 
Carolina with the Longleaf Pine. 

SEASONING OF GUM TDIBER. 

The vast quantities of Eed Gum and Tupelo in the Central and 
Southern States has led to repeated inquires as to their fitness for 
structural lumber, etc. A number of gum ties are now being cut by 
the Southern Pacific Railway, which will be piled and tested with the 
pine in Texas. 

PACIFIC COAST TESTS. 

On the Pacific Coast a number of timbers which were formerly 
ignored are coming into general use. Piling tests are being arranged 
for Western Hemlock and the various species of fir. In southern 
California tests are being conducted with the Eucah^ptus, to determine 
its fitness for ties and poles. 

XIII. CONCLUSIONS AND KECOMMENDATIONS. 

Timber seasoning is a practical method for increasing the length of 
life of both untreated and treated timber. At the same time it forms 
the most important preliminary step to successful chemical treatment. 
The cost of seasoning is insignificant, while the returns amount to a 
considerable sum in the end. With the increased cost and scarcitj- of 
timber, every step leading toward a more economic use of our supply 
ought to receive attention. 

It is perhaps too soon to draw final conclusions, but the following 
genera] recommendations can be confidenth^' made. 

(1) Green timber should be piled in as open piles as possible as soon 
as it is cut, and so kept until it is air dry. In the case of ties the 
7 by 2 form of pile is the best. No timber should be treated until it 
is air dry. 

(2) Timber treated with a preservative dissolved in water should be 
piled after treatment for several months at least to allow the water 
pressed into the wood with the salt to evaporate. Under no circum- 
stances should timber freshly treated with a water solution be exposed 
to weathering influences. 



APPENDIX. 



METHOD OF KILN DRYING IN USE BY THE FRENCH EASTERN 
RAILWAY. 

The French Eastern Railway maintains at Amagne a plant for completing the dry- 
ing of its ties after they have been seasoned in the open air, which consists of four 
kilns. These are structures about 50 feet long by 46 feet wide and contain two pairs 
of hot-air galleries, each pair of which is provided with an independent furnace and 
can be operated as a separate kiln. Between them is the supporting wall of the other 
two furnaces, each with its own chimney. The galleries are formed of vertical walls 
about 6 feet 4 inches apart, surmounted by a small circular arch with a radius of 3 feet 
2 inches. To diminish the loss of heat, the arches are covered with a bed of concrete 
about 8 inches deep over the keystone. Little trams, loaded with ties, travel the 
whole length of the galleries upon a tramway 3 feet wide, which, to make the cars 
roll easily, has a grade of 1 inch for 5 yards. 

The masonry supporting wall of the two furnaces for each kiln is about 16 feet long 
and 11 feet wide by 8J feet high. It is strengthened with rails arranged in vertical 
trusses, strongly joined at their upper ends. 

In escaping from the fire box of the furnaces the products of combustion rise to 
enter the uppermost of five horizontal rows of longitudinal conduits, five conduits to 
the row. From this they pass down again by circulating successively through the 
other four rows. The cross section of each conduit is about lOf by 4J inches. These 
conduits are inclosed in hollow brick sheating, through the passages in which a cur- 
rent of air is drawn in a direction counter to that taken by the smoke. To this 
ascending air the smoke loses all its heat, and is finally discharged into some pipes 
under the furnaces, communicating with sheet-iron chimneys about 40 feet high, 
placed inside accessory brick chimneys 26 feet high. 

The air enters, at first cold, from the outside into a lower chamber of the furnace, 
and becomes gradually heated in its upward progress. It is at last discharged into a 
hot-air chamber which occupies all the upper part of the kiln. From this it is car- 
ried down to the galleries in which the ties are dried by four vertical pipes, having 
a cross section of 18 by 18 inches. Two pipes open into each gallery, at the end of 
which the trams bearing the ties pass ciut after the drying has been completed. 

In passing through the galleries in a direction opposite to that in which the ties 
progress, the air becomes cooled, little by little, from contact with the wood. At 
the farther end it descends to be discharged into the accessory chimneys, in which 
a draft is created by a small fire box at the base. 

The opening and closing of all the hot-air pipes is regulated by means of registers. 
The smoke conduits may be easily cleaned by lifting the plates or plugs which close 
them at one end. 

Turntables at the entrance and the exit of the galleries enable the loaded trams to 
be started on their journey through, and at the end removed again to undergo treat- 
ment with tar oil in cylinders which receive one car at a time. Each tram carries 
about 40 ties, slightly separated from each other, so that all the faces may be in 
direct contact with the hot air in the galleries of the dry rooms and with the tar oil 

47 



4b SEASONING OF TIMBER. 

in the cylinders. The four kihis in all contain 16 galleries, with a capacity of 5 trams 
each, in all 80 small trams. It is thus possible to dry about 3,200 ties at one time. 
With an annual output of 400,000 ties, seventy-two hours would be allowed for the 
average drying period. 

The temperature of the galleries is at the maximum 30° to 35° C. at the entrance, 
and 70° to 80° C. at the delivery. As the trams are taken from the cylinders one at 
a time, the drying is progressive, and the wood, for this reason, is less lialile to split 
or warp. 

The temperature is regulated according to the state of the weather and the condi- 
tion of the wood. 

The material used for heating the dry room is composed of a mixture of small 
coal, cinders from locomotives, trimmings from shoe machines, and all the trash and 
chips from the wood yard. To turn out 400,000 ties the furnaces of the four dry 
rooms consumed about 200 tons 'of fine coal and 250 tons of the trimmings and wood 
trash, making 450 tons of the mixed fuel. This mixture develops a sufficient heat 
and offers the additional advantage of not wearing out the fire boxes by a too 
intense heat. The accessory fire places put at the bases of the chimneys burn briquets 
exclusively. For the output indicated above the eight accessor}^ fires burned 50 tons 
of briquets. The expense for fuel is about one-fifth of a cent for each tie. 

o 



IB Mr '07 



36 VI 






'>• .^^-n^ 



.' .1^°-. V 



J^^^.-^ 









■;^iixu'^^* rP fk. %^'*sss3t» *f* *^ :'iw^x* cp '^ *;*'*'s^. fl.^ ^ vests',* o' ■^ 









^ 9* *' 

















LIBRARY OF CONGRESS 



017 111428 7 # 



